Introduction
We are living in what is usually described as an 'information society' and as
the business community makes ever greater use of computers the courts are going
to find that increasingly the disputes before them turn on evidence which has at
some stage passed through or been processed by a computer. In order to keep in
step with this practice it is vital that the courts are able to take account of
such evidence. As the Criminal Law Revision Committee recognised, 'the
increasing use of computers by the Post Office, local authorities, banks and
business firms to store information will make it more difficult to prove certain
matters such as cheque card frauds, unless it is possible for this to be done
from computers' (CLRC 1972, para 259).

Admissibility

The law of evidence is concerned with the means of proving the facts which are
in issue and this necessarily involves the adduction of evidence which is then
presented to the court. The law admits evidence only if it complies with the
rules governing admissibility. Computer output is only admissible in evidence
where special conditions are satisfied. These conditions are set out in detail
in section 69 of the Police and Criminal Evidence Act (PACE) 1984 (see further
Nyssens 1993, Reed 1993 and Tapper 1993).

In general the principles of admissibility are that the evidence must be
relevant to the proof of a fact in issue, to the credibility of a witness or to
the reliability of other evidence, and the evidence must not be inadmissible by
virtue of some particular rule of law (Keane 1994, pp 15-20; Tapper 1990, pp 51-
61).

Real evidence usually takes the form of some material object (including computer
output) produced for inspection in order that the court may draw an inference
from its own observation as to the existence, condition or value of the object
in question. Although real evidence may be extremely valuable as a means of
proof, little if any weight attaches to it unless accompanied by testimony which
identifies the object in question and explains its connection with, or
significance in relation to, the facts in issue or relevant to the issue.

This is illustrated in the case of R v Wood (1982) 76 Cr App R 23 where the
appellant was convicted of handling stolen metals. In order to prove that metal
found in his possession and metal retained from the stolen consignment had the
same chemical composition cross-checking was undertaken and the figures produced
were subjected to a laborious mathematical process in order that the percentage
of the various metals in the samples could be stated as figures. This was done
by a computer operated by chemists. At the trial, detailed evidence was given as
to how the computer had been programmed and used. The computer printout was not
treated as hearsay but rather as real evidence, the actual proof and relevance
of which depended upon the evidence of the chemists, computer programmer and
other experts involved.

The difficulty in the application of this rule lies in its interaction with the
hearsay rule. Evidence is hearsay where a statement in court repeats a statement
made out of court in order to prove the truth of the content of the out of court
statement (Sparks v R [1964] AC 964). Similarly evidence contained in a document
is hearsay if the document is produced to prove that statements made in court
are true (Myers v DPP [1965] AC 1001). The evidence is excluded because the
crucial aspect of the evidence, the truth of the out of court statement (oral or
documentary), cannot be tested by cross-examination. (1) The problem, however,
occurs because some statements, although in form assertive and inadmissible if
they were to originate in the minds of human beings, in fact originate in some
purely mechanical function of a machine and can be used circumstantially to
prove what they appear to assert.

The basis for this view was laid down in a case having little to do with
computers. In the Statute of Liberty [1968] 2 All ER 195 a collision occurred
between two vessels on the Thames estuary. The estuary was monitored by radar
and a film of the radar traces was admitted into evidence. Simon P rejected the
argument that the film was hearsay - he held that it constituted real evidence
and not hearsay and he placed it on a par with direct oral testimony. Where
machines have replaced human beings, it makes no sense to insist upon rules
devised to cater for human beings but rather, as Simon P said 'the law is bound
these days to take cognisance of the fact that mechanical means replace human
effort' (at p 196).

This useful distinction was apparently overlooked in R v Pettigrew (1980) 71 Cr
App R 39 where the prosecution wished to prove that some bank notes found in the
possession of the accused were part of a particular consignment despatched by
the Bank of England. A computer printout was used to prove this but the Court of
Appeal held that such evidence was inadmissible under the statutory provision
concerned (section 1 Criminal Evidence Act 1965 - now repealed). The Court took
the view that the operator did not have the requisite personal knowledge of the
numbers of the bank notes rejected from the machine since they were compiled
completely automatically by the computer. This conclusion is quite accurate and
a perfect application of the hearsay rule but it failed to consider the use of
the print-out as real evidence. This confusion between hearsay and real evidence
is unfortunate and it may explain why it was necessary to create special rules
for computer evidence.

Criminal Proceedings

It is imperative that computer output should be readily used as evidence in
criminal cases since otherwise many cases, particularly those involving
dishonesty, would be immune from prosecution. At the same time one cannot be too
complacent about the technology since computers are not infallible. It is widely
acknowledged that 'hacking' and 'viruses' may affect information stored on a
computer. These factors were obviously taken into consideration when enacting
the provisions governing computer generated evidence in criminal proceedings.
(2)

Section 69 of the Police and Criminal Evidence Act 1984 provides that:

"(1) In any proceedings, a statement in a document produced by a computer shall
not be admissible as evidence of any fact therein unless it is shown-

(a) that there are no reasonable grounds for believing that the statement is
inaccurate because of improper use of the computer and;

(b) that at all materials times the computer was operating properly or, if not,
that any respect in which it was not operating properly or was out of operation
was not such as to affect the production of the document or the accuracy of its
contents."

In addition any rules of court made under section 69(2) must also be satisfied
(at the time of writing no such rules have been made).

Real evidence and hearsay

So far the discussion has focused on exceptions to the hearsay rule. However
evidence derived from a computer constitutes real or direct evidence when it is
used circumstantially rather than testimonially, that is to say when the fact
that it takes one form rather than another makes it relevant, rather than the
truth of some assertion which it contains. (3)

Direct evidence produced by a computer is not subject to the hearsay rule. As we
have already noted, in R v Wood calculations were carried out by a computer
specifically for the purpose of the trial to verify whether the composition of
stolen metals matched original metals. Computer output was admissible as real
evidence since it did not purport to reproduce any human assertion which had
been entered into it. It was held that the machine was a tool and that in the
absence of any evidence that it was defective, the printout, the product of a
mechanical device, fell into the category of real evidence. The court did
recognise, however, that the dividing line between admissibility of computer
generated evidence as real evidence or hearsay would not always be easy to draw.


The same distinction and result were reached in Castle v Cross [1985] 1 All ER
87 and in R v Spiby (1990) 91 Cr App R 186, CA an automatic telephone logging
computer which logged the call details without human intervention was admitted
as real evidence. The Court also held that, in the absence of evidence to the
contrary, courts would presume that such a computer was in working order at the
material time.

Thus as far as the common law is concerned the status of computer evidence as
real or hearsay will depend, in each case, on the content of the computer record,
the reason for using it in evidence and the way in which it was compiled. Cases
like R v Wood and R v Spiby, however, must now be read in light of the decisions
in R v Shephard [1993] 1 All ER 225, HL and R v Cochrane [1993] Crim LR 48, CA.
In R v Shephard the House of Lords held that section 69 PACE 1984 imposes a duty
on anyone who wishes to admit a statement in a document produced by a computer
to produce evidence that will establish that it is safe to rely on the document;
such a duty cannot be discharged without evidence by the application of the
presumption that the computer is working correctly expressed in the maxim omnia
praesumuntur rite esse acta; and it makes no difference whether the statement is
or is not hearsay. In R v Cochrane it was held that before the judge can decide
whether computer printouts are admissible, whether as real evidence or as
hearsay, it is necessary to call appropriate authoritative evidence to describe
the function and operation of the computer. In that case the prosecution wanted
to prove that certain cash withdrawals were made from a particular 'cashpoint'.
The machine would only dispense money if the correct Personal Identity Number
was entered. The matching was carried out by a mainframe computer and evidence
of its proper functioning was thus required by the court. The prosecution did
not adduce this evidence and the conviction was set aside on appeal.

As we have seen, a printout from a computer which has been used as a calculating
device, or which records information automatically without human intervention,
is admissible as real evidence and involves no question of hearsay. (4) On the
other hand, where the printout contains information supplied to the computer by
a person, it is hearsay if tendered for the truth of what is asserted, but may
be admissible under either sections 23 or 24 of the Criminal Justice Act 1988. A
statement can only be admitted under sections 23 or s 24 if its maker (or the
original supplier) had (or may reasonably be supposed to have had) personal
knowledge of the matters dealt with. Furthermore, under section 24 the 'creator'
of the document must have been acting in the course of a trade or business etc.
A statement in a computer printout which has satisfied the foundation
requirements of sections 23 or 24 can only be admitted on satisfaction of the
additional requirements contained in section 69. (5)

Section 69 is couched in negative terms making it clear that evidence which does
not satisfy its requirements is inadmissible. The object of section 69 is to
impose a duty on anyone who wishes to introduce a document produced by a
computer to show that it is safe to rely on that document and it makes no
difference whether the computer document has been produced with or without the
input of information provided by the human mind and thus may or may not be
hearsay (per Lord Griffiths in R v Shephard at p 228).The operation of section
69, therefore, is not limited to printouts that fall within sections 23 or 24 of
the 1988 Act. (6)

Reliability

If there is a dispute as to the admissibility of a computer printout in a
criminal case involving a jury, the judge should hold a voir dire. A party
seeking to admit a printout under section 24 (or section 23) must establish the
foundation requirements of both that section and section 69. The judge, in
deciding whether the prosecution has established these requirements, should
apply the criminal standard of proof. (7) Although, as we shall see, the
additional requirements of section 69 can be proved by certificate, the
foundation requirements of section 24 (or ...