ESDA and the analysis of contested interview notes
This paper was published in Forensic Linguistics 1 (1994):
In October 1987 I was asked to examine a set of documents. At that time
I had been working part time as a forensic document analyst for thirteen
years; this case, however, was different. It did not concern handwriting,
as the large majority of my previous cases had, but the use of ESDA: the
Electro-Static Detection Apparatus. I was asked to apply this machine to
the allegedly contemporaneous notes of three interviews with one Paul Dandy,
during which he had apparently confessed to the offence of armed robbery.
These notes had been taken by the Police-specifically, by members of an
elite unit in the local police force: the West Midlands Serious Crime Squad.
Of whom, at that time, I had not heard; nor had it ever occurred to me that
it might be a good idea to use ESDA on the disputed interview notes that
had cropped up from time to time in the course of my practice as a document
The West Midlands Serious Crime Squad is now famous, and so is ESDA, and
their names are inextricably linked. The Squad was disbanded in 1988 pending
investigation into a number of allegations of fabrication of interview notes.
After that, one by one, a chain of similar alleged miscarriages of justice
led to the release of people serving long prison sentences. These included
two of the most famous, notorious, crimes of this half of the century: the
murder of PC Blakelock in the Broadwater Farm riots and the Birmingham Pub
bombings. Before 1987 no-one who was either not a member of or in serious
contact with the criminal world took seriously the proposition that the
Police were capable of forging confessions. Since the chain of events that
I have mentioned, no-one believes anything other than that. At the heart
of this extraordinary reversal was ESDA, whose evidence was responsible
for most of the successful appeals; and there are those who believe that
it was the Dandy case that started this avalanche. Since the Dandy case
I have conducted a large number of these analyses of Notes taken by the
West Midlands Serious Crime Squad and other police forces, including the
Flying Squad, with results that ranged from negligible to dramatic. In this
paper I propose to tell part of the story of ESDA and the analysis of Police
Interview Notes. I will describe the ESDA machine and its functioning; I
will describe the Notes themselves and the rules governing their taking,
known as PACE: the Police and Criminal Evidence Act of 1984. I will describe
the techniques that have been developed to use ESDA for this purpose, and
the problems and pitfalls associated with these techniques. Finally, I will
give a detailed account of one case.
ESDA is an extraordinary machine. It brings to light evidence that was not
only hitherto completely invisible, but whose very existence was unknown.
It produces not just identification evidence, but text: evidence with content.
It can reveal whole narratives, and these narratives can reveal the crime
that has been committed. Paradoxically, since what we are dealing with here
is fabricated confessions, what it reveals amounts to a confession of this
fabrication: a text beneath the surface that tells the story of how the
fabricated text was created. This sometimes has the uncanny effect of taking
the investigator back in time, to the occasion, perhaps in some interview
room in the West Midlands in 1986, when the document was first written.
At its best, the effect of ESDA is almost magical.
What ESDA actually does is very simple. If you write on a piece of paper
that is resting on another piece of paper, it is quite likely that as you
write the pressure of the writing implement at its point will create indentations
on the sheet beneath. If there were carbon paper between the two sheets
you could read these indentations as blue or black images; without it, the
indentations are at best difficult to read, and usually more or less invisible.
ESDA reveals the indentations almost as effectively as carbon paper: if
you apply the ESDA process to the apparently blank under-sheet, the machine
produces a legible image of these indentations, even if there had been one,
two, or even three other pages intervening between the top copy that received
the writing in the first place and the page actually under examination.
When this happens, the results can be dramatic: suddenly, out of nothing,
as it seems, an entire text springs to life.
ESDA was invented in 1978 at the London College of Printing by D.J.Foster
and D.J.Morantz, in consultation with the Metropolitan Police Forensic Science
It works by an electro-static process, in much the same way as a photocopier.
The sheet of paper to be investigated is placed on a bronze slab. This slab
is earthed, and sintered: that is, it is perforated by tiny holes. Underneath
is a powerful (and noisy) pump, which, when switched on, sucks air through
the slab and holds the paper down flat against it. A sheet of transparent
polymer film (very similar to the food wrap known in the UK as 'cling-film')
is laid over the top of the paper, both to protect it and as an essential
but somewhat mysterious part of the process. The resulting sandwich (transparent
film, paper, and bronze slab) is then charged with static electricity: a
metal wand known as the corona discharge unit is passed over it. Inside
the wand is a thin wire with a potential of about 5,000 volts. As a result,
static electricity discharges itself to earth through the sandwich.
It seems that the conductivity of the sandwich differs at those places where
there are indentations in the paper, and this difference results in an electronic
image of the indentations being created on the sheet of film. This image
is developed, as it were, by allowing fine carbon granules to spread over
it, either by an aerosol process in a cloud chamber, or by inclining the
bronze slab at an angle and pouring the carbon granules, mixed with small
plastic balls which act as a carrier, across the surface. The granules stick
to the electrostatic image of the indentations, and the image becomes visible.
It is preserved by putting a sheet of adhesive plastic on top of the layer
of carbon, thus creating another sandwich (adhesive plastic, carbon, and
transparent film) which can be lifted away from the paper. This sandwich,
which has come to be known as an 'ESDA lift', contains the image of the
indentations and preserves it very effectively.
An ESDA lift, then, looks like a sheet of thin transparent plastic with
an overall grey tone formed by the tiny dots of carbon, in which the image
of the indentations is preserved in the form of local coalitions of those
dots, which appear as black, or at least darker grey, marks. ESDA does not
ignore any top copy writing that there may have been on the sheet under
examination, but it treats it in the opposite way from non-inked indentations:
top copy writing is developed as white lines against the grey, like a photographic
negative, and so is easy to ignore. This aspect in particular of the ESDA
process is not fully understood: why is it that the inked indentations of
top-copy writing are treated in the opposite way to the non-inked indentations?
Theories have been advanced, but none has won universal acceptance.
Nor, in practice, does it matter very much. We do not need to understand
how ESDA works to know that it does work, and to have complete faith in
the texts that this process reveals. All one has to do to be converted to
this belief is to see it in action: it is as immediately convincing as a
photocopier. Both processes result in conglomerations of carbon particles
that have coalesced to form images. These images are so obviously coherent
and significant that even if one didn't have the original source of the
images (the copied document, in the case of the photocopier, or the original
writing that had produced the indentation, in the case of ESDA) no-one is
likely to believe that the preserved text was an artefact produced by the
random distribution of carbon particles. It is immediately obvious that
the odds against this are almost limitless.
ESDA, then, provides compelling evidence, when it works. Sometimes it doesn't,
for whatever reason; perhaps there are no indentations on the sheet under
examination, or perhaps the indentations that are there have not reproduced,
though some incorrect combination of the distance of the wand from the bronze
slab, the surrounding humidity and its effect on the conductivity of the
paper, the amount of carbon, or whatever. ESDA is somewhat temperamental,
and its silences are deeply frustrating; but when it speaks, what it says
Which is why it has done what it did. In the West Midlands (at least) any
criminal lawyer will tell of a long series of complaints against the police
for fabricating evidence which have either failed for lack of evidence or,
more commonly, not even been brought to Court, for the same reason. An allegation
made by a suspected criminal against the forces of law and order has been
felt to need particularly convincing evidence to support it. ESDA has been
found to provide exactly this. But in order to understand the nature of
this evidence, it is necessary to understand the documents on which it has
been used: Contemporaneous Notes.
Contemporaneous Notes and PACE
There are strict rules governing the way in which interviews take place
between police officers and those they suspect of having committed crimes.
These rules are laid down in the Police and Criminal Evidence Act of 1984,
known as PACE. These rules were accepted as a Code of Practice early in
1986. What follows is not a description of PACE, because I am not a lawyer,
and do not have a lawyer's knowledge of these matters. Rather I will describe
the normal process by which Contemporaneous Notes are taken, subject to
PACE, from the point of view of the examination of the end product: the
The actual product of the interview is
 a set of unbound A4 pages. These are hand written on standard pre-printed
forms, according to a method determined partly by the Code of Practice and
partly by habit and convenience. This method differs from Police Force to
Police Force, but within each the practice is remarkably constant. The formalised
procedure that results in the production of these notes has at least three
protagonists: the interviewee, the interviewer, and the note-taker. The
note-taker takes a standard blank first page and begins by writing, in the
allotted spaces, the interview details: the interviewee's name, age, address,
the date, the location of the interview, and the names of the officers present.
A Caution will then be administered, which the interviewee is invited to
sign, in a box on the pre-printed first page. The note-taker will next enter
the start time of the interview, first in another box in the middle of the
interview details, and then (usually) in the left hand margin of the bottom
half of the page where the beginning of the interview proper is to be recorded.
The interview then begins, in the form of questions by the interviewer and
answers by the interviewee, and each is recorded, as it happens, by the
note-taker. There are six lines (in the forms used in the West Midlands)
available on the first page for the beginning of the interview; when this
space is full, continuation sheets are used, which allow 24 lines of writing.
The note-taker will not interrupt the difficult task of contemporaneous
note-taking to fill in the heading details and page numbers at the top of
each continuation sheet; only the text is written during the interview.
The Code of Practice insists that the Notes should be a verbatim contemporaneous
record of everything that is said and done in the interview. Interruptions,
for tea, for instance, or because of visits by a supervising officer, are
timed and noted.
When the interview is over the end time is recorded and entered, sometimes
at the end of the interview notes, but always in the box provided on the
first page. The notes are then read over to the interviewee, or he or she
is invited to read them; during the course of this reading the interviewee
is asked to sign every page of the notes and to initial any corrections.
The rereading done, the interviewee is (in the West Midlands, at least)
asked to write in his or her own handwriting at the end of the interview
what is known as the Caption: a short formal statement to the effect that
the interview has been properly conducted and the notes are a true record
of the interviewee's own words. This is signed, and then the Notes are 'topped
and tailed': that is, the note-taker enters the Heading-the full name of
the interviewee-at the top of each continuation sheet, and the page number,
then then signs the page in the space provided at the bottom; then the interviewing
officer also adds his signature at the bottom of the page.
This is what happens from the point of view of the protagonists-when an
interview is conducted properly. From the point of view of ESDA analysis,
which, it will be remembered, depends entirely on impressions indenting
through from a top copy on to sheets placed beneath it, there is one crucial
item to be added. The entire success of ESDA in the analysis of interview
notes derives from one simple human preference: the fact that people do
not like to write on a hard surface. Particularly the hard and not utterly
flat surface of the tables found in interview rooms, which have normally
seen a good deal of wear and tear. Some form of pad makes a much more satisfactory
basis for writing, and, since the pre-printed interview forms come in loose
stacks rather than bound pads, the obvious thing to do is to make a squared
pile of these sheets and write on them from one to the other, down through
a stack. The end result is that while the note-taker was transcribing the
interview he or she was also, unknowingly, leaving an invisible duplicate
of the written text of each page on the page beneath. From the point of
view of this invisible record, then, the following scribal habits are of
vital importance. The usual practice is that when the interview begins,
the note-taker will take a first page and place it on a stack of continuation
sheets. Each page is then filled in using the rest as a pad to support the
writing page. When the interview is finished, the normal pattern is for
the topping and tailing to be done with all of the sheets in a pile, so
that, like the text, the headings, page numbers, and signatures will indent
through from one page to the next, though the text writing represents one
consecutive writing sequence, and the addition of the details another. Last
of all the end time is entered on the first page, often, but not always,
while it is resting on a stack of continuation sheets.
When all of this has been done, the Notes are delivered to the Custody Sergeant.
This officer plays an important role in the proceedings under PACE. It is
his or her task to act as an independent check that the rules of PACE are
complied with. Since the Custody Sergeant is based in the Police Station
where the interview takes place, and is not a member of the investigating
team of detectives, it is assumed that he or she will be independent of
any possible attempt to falsify the record. This officer keeps a Custody
Sheet, which is a carefully timed account of everything that happens to
the suspect in custody, including all interviews and other visits by police
officers. It has boxes that should receive all of the details of the suspect,
including one box that has the following headings:
I want a solicitor as soon as practicable
The interviewee is invited to cross out one of these options, and sign it;
the entry is timed and dated. When the custody officer receives the Notes,
he or she will count the pages and check that they have been headed, signed,
and numbered; he or she may also decide to read the Notes. They are then
(usually) handed back to the arresting officer to be taken and kept in (for
instance) an incident room, together with the other evidence.
I do not want a solicitor at this time
If all of the conditions have been complied with, and particularly if the
notes have been signed by the interviewee, the resulting pile of sheets
becomes evidence: it can be used against the suspect in order to obtain
a conviction. But, and here is one of the main causes of contention, if
they are not signed they can still be used as evidence, if in a different
way: an officer can testify on oath that the interview took place as set
down in the notes, and they can be read out and used as evidence. On occasion
unsigned contemporaneous notes have been the sole basis for conviction.
Using ESDA on contemporaneous notes
I will now give an outline of two of the ways in which we can use ESDA in
the analysis of interview notes: specifically, I will describe some of the
uses of alignment and misalignment, and the evidence for rewriting. 
The first thing to do is to determine whether there are any indentations
on the ESDA lift. If not, analysis obviously stops there. It is sometimes
tempting to construct a theory on the basis of the non-appearance of indentations
in ESDA lifts, but this is a dangerous argument because ESDA may simply
have failed to register, for whatever reason, indentations that are in fact
present. Many factors combine in indeterminate combinations to produce a
good set of ESDA lifts, and it is not uncommon for one analyst to discover
more than another, equally competent, expert, simply because of this element
Usually, however, the ESDA lift will show some record of indentations. The
clarity of the realisation of these varies very considerably: sometimes
they can be read almost as easily as top-copy writing, but for the most
part they fall somewhere in a scale ranging from difficult to impossible.
One of the main factors affecting this clarity is the writing implement
used. In the West Midlands the Serious Crime Squad made life much easier
for analysts of ESDA lifts by preferring in the large majority of cases
to use ball-point pens. In the Metropolitan Police, however, there is (I
am told) a custom that when an officer is promoted to the C.I.D. he or she
will go out and buy a fountain pen. Fountain pens deposit a line of ink
without needing much pressure, and the result is often either no detectable
indentation at all, or a set of pale grey lines only barely emerging from
the surrounding grey fog of an ESDA lift. Attempting to decipher these is
not a pleasant activity. All of this is exacerbated by a curious characteristic
of ESDA. If it is applied to the indentations of a page of writing, written
continuously from top to bottom, it is common that the indentations recorded
by ESDA become fainter, often to vanishing point, as they proceed down the
page. Why this should be is not known.
Fortunately, however, it is not usually necessary to read the indentations,
because they will derive from existing writing: normally from the previous
page. So if an ESDA lift has indentations on it, the first thing to do is
to find out where they come from. The transparent ESDA lift is superimposed
on a photocopy of the previous page. If the indentations derive from this
page it is usually very easy to see that this is the case: since the same
act of writing produced both top copy and indentations, the match, or register,
to borrow a term from printing, between the two will be exact, leaving no
doubt as to where the indentations came from. Even very faint or partial
writing can be traced to its source in this way, and the need for the labour
of reading the indentations is removed.
If the source of the indentations can be determined, then the next matter
to concern the examiner is that of alignment. The normal pattern is for
the pages to have been squared during the act of writing into a more or
less neat pile of sheets: if not, then presumably the pad function of the
pile of sheets would be impaired. The result is that when the examiner superimposes
the transparent ESDA lift on the source page the indentations will more
or less superimpose down the page. But not exactly: during the act of writing
the paper will characteristically have shifted slightly as the hand moves
downwards in the act of writing, disturbing the relationship between the
top page and the one underneath. As a result, the entire set of indentations
will not be in one register, but in several different registers of up to
as much as ten lines or so each. The heading details (the interviewee's
name and page number), since they are usually added after the end of the
interview in a separate act of writing, will also not be in register with
the text, and the three signatures at the bottom (interviewer, interviewee,
and note-taker) will for the same reason not be in register with the text
or indeed with each other, since there will inevitably have been a shift
in the top page against the pad between the different signings.
This is the normal pattern of alignment. Disturbances in that normal pattern
are what the examiner is looking for. For instance, in one Interview I have
examined three consecutive lines read:
R I was standing by the phone box keeping watch
These lines indented on to the next page, and the first part of the first
line and all of the second line and third lines were in one exact register
with the indentations they made. However, crucially, the words 'keeping
watch' were out of this alignment. The result can be shown in a stylised
way in this diagram:
Q What did you all do then
R We ran back to the car
The bold type shows the exact superimposition of original and indentation;
the contrast with the non-register of 'keeping watch' is even more striking
in the original. There are two possible ways of explaining it: either the
words were written in the correct sequence and the paper shifted twice,
the second shift bringing it exactly back to where it was relative to the
sheet underneath before the first shift took place; or else the words 'keeping
watch' are a later insertion. The first possibility is so unlikely that
this kind of evidence is taken (and in this instance, was taken) as a strong
indication that the misaligned words were added afterwards, and out of sequence.
As the Lord Chief Justice put it in the Court of Appeal, when this evidence
was presented to him, 'it doesn't inspire confidence, does it?'
Note, however, that in this case, as usually in the interpretation of ESDA
material, there are two components. One is to do with the physical evidence:
the disposition of marks on a sheet of paper and an ESDA lift. The other
is to do with content. The physical evidence in this instance is strong
that the two words 'keeping watch' were added at some point after the aligned
text was written: either immediately after, or at some undetermined point
after that. But one cannot ignore the content: if the added text is trivial,
then its significance is also trivial: an innocent afterthought, perhaps,
added a few lines later. PACE requires that any additions or corrections
in the interview should be initialed by the interviewee, but it would look
absurd to initial an invisible correction. I have seen a number of examples
of minor additions and corrections revealed by ESDA which have not been
initialed, and no-one would consider making an issue of this. However, in
this case the addition is quite evidently not trivial: 'I was standing by
the phone box' is not incriminating, but with the addition of 'keeping watch'
it becomes an admission to a crime. Normally the task of the document examiner
is to make statements about the physical characteristics of the document;
its content is the province of the lawyers who conduct the case, and the
Court who will determine its outcome. Document examiners don't spend much
time reading the documents they examine. But the special ability of ESDA
is to reveal new textual material, evidence with content, whose significance
can only be determined by reading it, and this has, I suggest, the inevitable
effect of bringing the document examiner into the difficult area of textual
Another use of the study of alignments is in the examination of start and
finish times. Normal practice is to record the start time at the appropriate
place in the interview details on the first page, record the interview,
and then enter the finishing time, again on the first page. This is usually
shown in the ESDA lifts, in that the finishing time will be out of alignment
with the text that surrounds it, showing that it is a later insertion. If
however the finishing time is in exact register with the start time and
the other heading details then this tiny fact is, potentially, of momentous
consequence: it suggests that when the interview details were filled in
the note-taker knew when the interview was going to end. Which is impossible,
if the subsequent pages are a contemporaneous note of an interview that
had not yet taken place. Therefore the evidence suggests that the entire
set of notes is a fabrication.
The problem here is that this is a major conclusion from a tiny detail;
a detail, moreover, that it is sometimes hard to be certain about. Misalignment
is obvious: alignment, not so. ESDA lifts are fuzzy, for one thing; another
problem is that one must be aware of the edge of the paper: it is a natural
action to square a stack of sheets by dropping the bottom and then the sides
against the flat surface of the table. If one alignment is square relative
to these two edges, then it would be possible (though, I suspect, difficult)
to recreate the same alignment by this squaring process at some later point.
If the indentations do not align with anything on the previous page then
the usual circumstance is that they are in a different handwriting, and
derive from some other interview. One common occurrence is that the note-taker
has come to the end of a pile of sheets and started on a fresh pile, the
top of which had previously been underneath when a different interview was
transcribed. In these cases it is (unfortunately for the eyesight of the
analyst) important to transcribe as much of the text thus revealed as possible.
The other interview can often be traced, and its date and time determined.
If it can be dated significantly after the date of the interview under examination
this would obviously give cause for suspicion that the notes of the latter
were not written on the date when the interview took place, which would
be good grounds for suspecting fabrication.
If, however, the indented writing is in the same hand as the rest of the
interview, but does not derive from the previous page, then it must be traced
to its origin. Sometimes it may originate from top copy writing in a different
interview that is part of a set of interviews of the same suspect. Tracing
this origin through perhaps dozens or even hundreds of pages is not easy
by hand, but there is a simple solution to this problem: the interviews
can be transcribed into a word processor, and an ordinary computer search
routine will either find the source immediately, or show with some definiteness
that the text is not to be found in that set of notes. The computer can
effortlessly trace all of the occurrences of even a few letters in part
of a word, and, if care is taken to circumvent the possibility of mistranscription,
even fragments can be sourced in this way. Once the source is found, superimposition
will (as usual) often reveal the meaning and origin of indentations otherwise
too faint to read.
If the indentations do derive from some other interview in the same sequence,
then one has an anomaly that can sometimes suggest tampering, if other evidence
supports this possibility. Essentially there are two possibilities. It is
not uncommon for officers to have the notes of an earlier interview present
when conducting an interview of the same suspect, though it would be unusual,
I imagine, for these notes to find their way into the pile of blank sheets
that is normally used as the writing support and thus receive indentations.
On the other hand, to concoct an interview it is essential that it should
be consistent with other interviews, and therefore very desirable to have
other Notes available for cross-reference. Of course this does not in itself
prove anything; however, I can say that I have not seen a set of notes in
which this phenomenon occurred without there having been other evidence
of tampering to go with it.
If the indented writing cannot be made to superimpose on any writing that
belongs to any related interviews, but is in the same hand as the interview
under examination, then the possibility of rewriting arises. The evidence
for rewriting must be a matter of interpretation of content. The physical
evidence is that indentations occur which are in the same hand as that of
the note-taker of the notes under examination, but cannot be traced to any
extant writings that one has. This in itself, however, is not necessarily
significant. What is important is that the indented writing should have
a clearly similar content to some piece of top copy writing, but not derive
from the same act of writing that produced that top copy writing. If so,
then we can suggest revision.
Though unacknowledged rewriting is necessarily a contravention of the PACE
rules, it need not be a serious one: occasionally, for instance, two or
three lines of indented writing are found at the top of a page that are
almost exactly the same, with a small variation. In one set of notes that
I examined the following indentations were found:
throw any bombs or prepare them?
The indented text ended abruptly at this point. The writing was in the same
hand as that of the note-taker of the notes in question, and was in register
with nothing on the previous or any other page; but on the page where the
indentations were found the first three lines read as follows:
I had three bottles of milk I gave them
Stix & he poured the milk out
throw any bombs or prepare them?
How does one interpret this material? A reasonable, indeed obvious, assumption
is that the interviewee said the indented text, and had it recorded so that
it indented into the next blank sheet. He then changed his mind: not Stix,
but Stix's mate was the one who poured the milk out. The recording officer,
perhaps in recognition of the importance of this change, instead of recording
it and having it initialed, since only three lines on an otherwise clean
page had been written, simply threw away the early version and began again
on the next blank sheet in the pile-unaware that this sheet had received
the indentations of the first attempt. Thus this small contravention of
PACE was preserved, invisibly, until ESDA brought it to light.
I had three bottles of milk, I gave them
to Stix's mate & he poured the milk out
This is a simple example of the analytic method that one uses in investigating
ESDA evidence, but it shows very clearly the process, and the fascination,
of the method. There are again three components: the physical evidence,
the interpretation of that evidence, and the use of that interpretation
for a suggested reconstruction. If the reconstruction is as plausible as
this one, then the fascination is evident: an intellectual puzzle is solved,
and a hidden piece of the past suddenly, unexpectedly, crystallises into
Not all rewritings are as innocuous as this one. This, finally, is what
has made ESDA famous: when it brings to light what can be taken as an early
and discarded version, just as in the above example-but with a crucial difference:
the current version contains incriminating material that is lacking in the
newly discovered early version. In the case of Paul Dandy the key evidence
against him consisted of two admissions allegedly made during one interview.
Since Dandy vehemently protested his innocence, the admissions were contested.
The second of the two admissions occurs in the following passage: it is
printed in bold type.
[WER] WILL YOU SIGN AN AUTHORITY
On the last page of an earlier interview with Dandy the following indentations
were found (square brackets indicate conjectural readings):
FOR US TO LOOK AT YOUR BANK ACCOUNT?
I TAKE IT FROM YOUR EARLIER REPLY
THAT YOU ARE ADMITTING BEEN INVOLVED
IN THE ROBBERY AT THE MEB?
YOU'SE ARE GOOD, THURSDAY, FRIDAY,
SATURDAY, SUNDAY AND YOU'VE CAUGHT
ME NOW YOU'VE GOT TO PROVE IT
DO YOU WANT TO READ OVER THE
[NOTES SIGN] AND CAPTION THEM
ILL INITIAL THE MISTAKES BUT
I WON'T SIGN THEM
WILL YOU SIGN AN AUTHORITY
The similarity of content, together with the physical evidence, shows beyond
reasonable doubt that another version of an extant page existed at some
point, and moreover that this version lacked the incriminating pair of sentences
printed in bold type. A reasonable reconstruction would suggest that the
indented version was earlier, and discarded in favour of a later version
that was offered in evidence, which had the incriminating sentences added
to it. Whether this was done without, or, as the officers involved were
later to allege, with the consent of Paul Dandy, cannot be determined from
this evidence alone. But the possibility of its having been done without
his knowledge was strong enough to persuade the judge in his trial to dismiss
the case against him immediately.
FOR US TO LOOK AT YOUR BANK [ACCOUNT]
DO YOU WANT TO READ OVER [THE]
[NOTES SIGN] AND CAPTION THEM
I'LL INITIAL THE MISTAKES BUT
[I] WONT SIGN THEM
What I have done so far in this account is to outline some of the basic
strategies that one uses in examining ESDA lifts of contested contemporaneous
notes. But that is not where the fascination of this work lies. Each case
is a unique puzzle: an enigma, that can, if one is lucky enough, be forced
or cajoled into revealing its truth. To illustrate this I will now give
an account of an actual case in detail.
The Lewis case
George Glen Lewis heard of my work with ESDA and interview notes in February
1991. He phoned me from prison and asked me to help him; he was serving
two concurrent sentences amounting to ten years for three robberies, all
on the basis of two uncorroborated confessions, the first of which was obtained
by members of the West Midlands Serious Crime Squad. This, as I understand
it, is his story. Mr Lewis lived in Wolverhampton, a small town in the Black
Country near Birmingham. In January 1987 his car, he said, was stolen, and
he reported this theft to the local Police. They told him that the car had
been found, and he went down to the Police Station to pick it up. There
he discovered that his car had been used in a robbery, and that he was the
prime suspect. He was arrested, protesting vigorously, and taken to another
Wolverhampton Police Station, Red Lion Street, for questioning. He refused
point blank to answer any questions without his solicitor being present,
and in general contested the whole business with some force: there seems
to have been a fight at one part of the proceedings.
I began to shout and swear at the Police officers and I was
told to go through into the back charge office. I refused, and eventually
two officers came and grabbed me and tried to push me through into the Office.
I resisted, and eventually other officers came over and I was overpowered.
I was handcuffed on the floor and then taken through into the back office
and put in a cell.
When his solicitor arrived he made a statement denying any involvement with
the burglary, and was released on bail without charge, with an undertaking
to return at a later date.
The following Wednesday two members of the West Midlands Serious Crime Squad
found him in a friend's flat and arrested him again. In the car he was,
he says, 'verbally and physically abused'.
In the Police Station one of the arresting officers took several
blank statement sheets from a drawer and told me to sign them. This I refused
to do. He punched me on the back of the head. I still would not sign the
blank sheets. Another officer whom I do not know and cannot name pulled
out a syringe needle and a phial with a clear liquid in it. He said 'This'll
make the black bastard talk'. ... I honestly believed he was going to drug
me with the syringe. I am absolutely scared of needles and the sight of
the syringe worried me. I then said that I would sign whatever statement
paper they wanted me to. [They] gave me a pen and stood behind me looking
over my shoulder saying 'sign there', and pointing at the parts where he
wanted me to sign ... Bearing in mind that no-one knew where I was, I was
under no illusions that these officers would seriously harm me.
The Police officers then, he claims, in front of him, wrote out two confessions
to three separate robberies.
I was crying and upset and kept on saying 'Why are you doing
this to me?' They said 'Because you fucked them about last week' ... [they]
kept going on about how I had fucked them about last week and that I had
now been well and truly fucked.
The interviews as recorded in the Notes of course present quite a different
picture. In them Mr Lewis decides from the beginning to confess everything.
Given the fact that a week earlier he had adamantly refused to say anything
without a lawyer being present, the officers ask him why:
DS Firstly let's talk about the burglary that happened last
week at Tettenhall.
When the Notes were complete Mr Lewis was allowed (in his account) to summon
his lawyer. This is the lawyer's story:
A The Police have already interviewed me about it. I did it.
DS Well tell me why are you admitting this to us when you denied it previously.
A Look you're in the Serious Crime Squad. I don't want to fall out with
you lot but I will tell you about everything. DS What do you mean everything
A Look I'll tell you what you want to know.
I requested to see my client but I was kept waiting for a period
of approximately 10 minutes. When I was admitted through to the charge area
the officers involved in the case were just scuttling out of the back entrance
... [Mr Lewis] was tearful and his first words to me were Mr Dawson they've
fitted me up with burglaries and robberies which I didn't commit. I immediately
asked him why he had not sent for me immediately when he was arrested. I
assumed from his experience the previous week at Red Lion Street he would
know to do this. He said that he had wanted to send for me and that when
he was deleting the line "I do not want a solicitor; his hand had been
knocked aside so that he was unable to complete the deletion. I immediately
left the room and went to examine the prisoner in custody sheet and saw
that what he had told me was true.
As indeed it was: the custody record has a horizontal line drawn through
the first three words of the printed sentence 'I do not want a solicitor
at this time', as if to begin to erase them; the line then angles sharply
downwards for about 1 cm. David Baxendale, the Home Office expert who was
asked to examine this material, commented that this evidence was 'in keeping
with the writer's hand being knocked away when the ... line was being drawn.'
This evidence (though not Dr Baxendale's interpretation of it) was used
in Mr Lewis's trial, and in a complaint that was made to the Police Complaints
Authority. The complaint was unsuccessful, as was Mr Lewis's defence at
the trial: he was sentenced to ten years imprisonment, almost entirely on
the basis of these allegedly false confessions. He was subsequently refused
leave to appeal.
Two years later the West Midlands Serious Crime Squad was disbanded, in
disgrace, and a massive investigation was conducted into all of its disputed
cases, among them that of Mr Lewis. David Baxendale was asked to examine
the ESDA evidence of the two interviews. His conclusion was that the ESDA
evidence showed nothing of any significance. In the first interview the
text had not indented through from one page to the next: there were indentations
of signatures and page numbers, as part of the 'topping and tailing' process,
and the last page bore some indentations from another interview, but nothing
else. It is reasonable to assume that each page had been written out while
resting on the table top, or some other pad, and not on a pile of blank
sheets: unusual, but not of any interest. As he said: 'The evidence as to
whether or not these notes were compiled in an irregular manner is essentially
The second interview had more material, including some anomalies. The text
of each page indented on to the next page, in the normal fashion, but the
last page had no indentations from the page before. This is odd, but not
necessarily of any significance at all. The heading details and police officers'
signatures, where they could be deciphered, appeared also to indent in a
regular fashion, from one page to the next. The other anomaly, however,
was in the pattern of indentation of the Lewis signatures. He found the
following: the Lewis signature on page 2 indented on to page 3, as one would
expect, but that on page 6 derived from the previous page, page 5; similarly
the page 6 signature indented on to page 5. He found no Lewis signature
indented on to page 6, but on page 7 he found a Lewis signature indented
that derived from an original on page 3. This is odd, but not itself evidence
that casts doubt on the authenticity of the Notes: it could simply be an
inexplicable anomaly, the product of some unique set of circumstances: the
notes were shuffled, for whatever reason, when Lewis signed them. Accordingly,
he concluded that there was no evidence to suggest that the notes had been
That was where the matter stood when I received the notes for examination
in 1991.  I took fresh ESDA lifts, and examined the ones that David Baxendale
had used: essentially, I agreed with his report. Was there, then, no more
to be said? It was hard to leave it at that. Not just the vivid circumstantial
detail of Mr Lewis's account, or the obvious misgivings of his lawyer, or
the evidence that suggested that he had been prevented at one point in the
proceedings from seeing a solicitor; there was a feeling that somewhere
in the ESDA prints was a solution, if only one could find it. My two colleagues,
Kelsey Thornton and Claire Marshall, and I spent many hours wrestling with
this enigma. Eventually the following hypothesis emerged.
In interview two the text of the questions and answers indents
from one page to the next in a regular fashion, with the exception of the
last page, which has no indentations from the text of the preceding page.
The pattern of the signatures was, however, different. Prolonged examination
of the vague patterns of grey dots that hover on the edge of legibility
revealed the following. It was possible to add to the indentations found
by David Baxendale to make a more complete picture of the pattern of indentations
of the signatures. In my report I wrote:
The signature from page 2.2  indents on to 2.3, as would
be normal, but that on 2.3 indents on to 2.7. The Lewis signature on 2.6
indents on to 2.5, and that on 2.5 on to 2.4. The signature indented on
2.2 is not clear enough to determine its provenance exactly, but it is not
inconsistent with the possibility that it was produced by the signature
on 2.4. This suggests that when the pages were signed by Mr Lewis they were
in the following order:
This new order (which was agreed by David Baxendale in a comment on my report)
is interesting, because it is beginning to look like a pattern:
2.6 : 2.5 : 2.4 : 2.2 : 2.3 : 2.7
The pattern is that the new order is almost a reverse of the order of the
text pages. Now, Mr Lewis says that he was induced into signing a number
of blank sheets. Supposing, as he signed each one, he placed it face up
on top of the previous one, including 2.7; but he also, as well as signing
it, wrote a caption on 2.7, thus producing a pile of sheets in reverse order.
Separately, on a page from a pile of blank first pages, he signed 2.1, whose
signature is not found indented anywhere. This gives us the following sequence:
2.7 : 2.6 : 2.5 : 2.4 : 2.3 : 2.2
with 2.1 kept separate because it is on a pre-printed first page form. In
the course of writing the notes out, the officers would first fill in page
1, and then take the pile page by page in the above order. The top page,
2.7, since it had a caption on it and would therefore have to be the last
page, would be put aside, and the rest filled in the order presented in
the pile, except that 2.2 and 2.3 somehow got transposed. Finally 2.7 was
filled in, and the Notes were then topped and tailed as usual.
There is no doubt, I think, that this is an interesting hypothesis. It is
only that, of course. It is not an opinion as to what took place in Wednesfield
Police Station between 7.55 and 8.35 pm on January 21st 1987. It is a possible
reconstruction: what the Police call a 'scenario'. It has strengths and
weaknesses. It strength is that it accounts for all of the evidence at hand,
including both the ESDA evidence and Mr Lewis's version of events. This
latter point is a considerable strength, since his story can be said to
have predicted the evidence of ESDA. It does not speculate, in the strictest
sense of the word, since it does not make up extra items of the story to
account for inconvenient anomalies in the data-except in one instance, which
is its greatest flaw: it is forced to rely on chance to explain the transposition
of 2.3 and 2.2. Its weakness is simply that it does not compel assent: the
natural reaction would be perhaps to applaud its ingenuity (if one were
feeling generous) and to say, yes, it could have happened that way, but
it need not have done.
In my report I wrote:
This reconstruction is of course highly conjectural. It is however
coherent, and it explains the evidence of the ESDA indentations, which are
otherwise hard to account for.
David Baxendale was not impressed:
The pattern of the impressions of the "Lewis" signatures
... could also have an innocent explanation. For example, Lewis could have
jumbled up the sheets while he was reading them, and then signed them without
putting them back in order.
This is indeed true, but as an alternative hypothesis it leaves something
to be desired. It does not address itself to the specific phenomena under
examination, namely the actual and particular order to the signings as revealed
by ESDA. It says that that order could have happened by chance. This is
true, but it is trivially true: anything can happen by chance. The number
of possible chance shufflings of seven pages are seven factorial: 80640
possible combinations. So the odds against these seven pages falling by
chance into that particular order (or any particular order) are 80640 :
 At least. It could be argued that we are not talking about one sequence
of seven pages (the signing order) but about two linked sequences: the text
order and the signing order. Both these sequences are explained by the Davis
hypothesis. To explain them by chance (the Baxendale hypothesis) would be
to maintain that chance determined these two sequences out of a possible
7 factorial squared other combinations that chance could also, with complete
impartiality, have provided. In this view, the odds against the Baxendale
theory are 6,502,809,600 : 1 against. I would maintain, therefore, that
the Davis theory, though weak in the ways described, is the best there is,
in that no better has been proposed.
The question is, once it has arisen, what does one do with it? To propose
hypotheses for refutation is a perfectly valid scientific procedure; indeed,
it is generally maintained that this is the defining procedure of science.
But in this case its merits and demerits are ultimately a matter not for
science, but for law, which operates different criteria when determining
the value of a theory. It is the task of the Defence to demonstrate to the
satisfaction of a Court that there is reasonable doubt, and no more than
that, about the guilt of an individual. 'Reasonable doubt' seems to be a
rather elastic concept, perhaps deliberately or at least necessarily so:
it seems to be, in the last analysis, determined for individual cases by
what happens to those cases in particular Courtrooms on particular days.
I would suggest that, given that elasticity, it is the task of a scientific
expert working for the Defence to point out to the lawyers employing him
or her any possible interpretation of the phenomena that may possibly be
of assistance in establishing reasonable doubt. It is then for the barrister
to judge as to the utility of this material for his or her task, and the
Court to judge as to its final value.
I sent my report to the Defence on 21st May 1991. They sent it to the Home
Secretary, who gave Mr Lewis leave to appeal. On March 24th 1992 Lord Lane
in the Court of Appeal ordered a retrial. This retrial took place in the
week beginning July 20th 1992; on July 22nd the Judge ruled that the confession
evidence was inadmissible, the prosecution offered no further evidence,
and Mr Lewis was found not guilty. He had served seven years of his ten
Tom Davis 11/9/92