Expert witnesses: a crisis in the criminal courts

Last month the House of Lords Science and Technology Committee published a report on the critical state of forensic science in the United Kingdom. Several private forensic science providers are close to financial collapse. At the same time the police are increasingly taking forensic science in-house – raising obvious questions of independence and impartialityor outsourcing it to unregulated providers that do not met minimum quality standards.

The evidence we received points to failings in the use of forensic science in the criminal justice system and these can be attributed to an absence of high-level leadership, a lack of funding and an insufficient level of research and development. Throughout this inquiry we heard about the decline in forensic science in England and Wales, especially since the abolition of the Forensic Science Service.”

Professor Claude Roux, President of the International Association of Forensic Sciences, told the Committee:

When I was a student, England and Wales held, essentially, the international benchmark. It was the “Mecca” for forensic science. Some 30 years later, my observation from the outside … is that it has been an ongoing national crisis and, at this stage, is more of an example not to follow.”

This report was alarming enough, but the problem with expert evidence in criminal cases goes much deeper even than the alarming House of Lords report suggests.

Such evidence is not confined to forensic science, and the dubious status of some of the expert witnesses who appear in the criminal courts was highlighted by a fraud trial that collapsed last week.

The carbon credit “expert”

The case involved 72 investors who had been persuaded to invest a total of three and a half million pounds in “carbon credits” (there were also allegations of frauds based on diamond trading but that need not detain us here).

Carbon credits are licences issued by governments which allow the holders to emit a certain quantity of greenhouse gas. They do not have to be used by the company to which they are originally issued: they can be traded, so a company has an incentive to reduce its emissions, whereupon it can then sell its licence to emit to someone else who may need it, or who may simply wish to trade in it themselves. I don’t begin to understand the way this “secondary” market in carbon credits works, but it is pretty obviously something in which it is unwise for an amateur to dabble.

All 72 investors were amateurs. They were financially naive, many were elderly, and some had been cold-called. Many had been told blatant lies. Once they had handed over their money to the slick salesmen, it almost all vanished. The prosecution case was that they were the victims of a calculated, sophisticated and cruel fraud.

In order to prove this the prosecution needed an expert witness to explain the world of carbon credit trading to the jury, and to explain why they should never have been sold as a suitable investment for individuals.

In previous trials they had used, with success, an “expert” on carbon credit trading called Andrew Ager, and so they turned to him again. The broad thrust of Mr Ager’s evidence was that there was virtually no secondary market in carbon credits. Anyone buying them was thus almost certain to lose money.

What is an expert witness?

He may well have been right. Whilst he had no academic qualifications he did have long experience in the arcane world of carbon credit trading.

There is no legal requirement for an expert witness to possess paper qualifications. It was explained in Silverlock [1894] 2 QB 766, where the expertise in question was handwriting comparison:

” … the witness who is called upon to give evidence founded on a comparison of handwritings must be peritus; he must be skilled in doing so; but we cannot say that he must have become peritus in the way of his business or in any definite way. The question is, is he peritus? Is he skilled? Has he an adequate knowledge? Looking at the matter practically, if a witness is not skilled the judge will tell the jury to disregard his evidence. There is no decision which requires that the evidence of a man who is skilled in comparing handwriting, and who has formed a reliable opinion from past experience, should be excluded because his experience has not been gained in the way of his business……”

Moreover, the areas of expertise on which an expert witness can give evidence are very wide. It was put like this by Bingham L.J. (as he then was) in Robb (1991) 93 Cr. App. R. 161:

The old-established, academically-based sciences such as medicine, geology or metallurgy, and the established professions such as architecture, quantity surveying or engineering, present no problem. The field will be regarded as one in which expertise may exist and any properly qualified member will be accepted without question as expert. Expert evidence is not, however, limited to these core areas. Expert evidence of finger-prints, hand-writing and accident reconstruction is regularly given. Opinions may be given of the market value of land, ships, pictures or rights. Expert opinions may be given of the quality of commodities, or on the literary, artistic, scientific or other merit of works alleged to be obscene ( Obscene Publications Act 1959, s.4(2) ). Some of these fields are far removed from anything which could be called a formal scientific discipline.”

There are limits though:

“… the courts would not accept the evidence of an astrologer, a soothsayer, a witch-doctor or an amateur psychologist and might hesitate to receive evidence of attributed authorship based on stylometric analysis.”

(“Stylometric analysis,” for those who have never come across it, is the analysis of writing to establish authorship. It is the sort of thing that leads some people to believe that Shakespeare’s plays were written by Marlowe, or not, as the case may be. I am not sure that it is quite such junk science as Bingham L.J. hinted, but I don’t profess to any expertise on the subject.)

The classic test nowadays comes from the case of Bonython [1984] 38 SASR 45:

“… whether the subject matter of the [expert’s] opinion forms part of a body of knowledge or experience which is sufficiently organized or recognized to be accepted as a reliable body of knowledge or experience.”

In the Sulley case, the defence objected to Mr Ager’s expertise, and the judge was thus required to hold a “voire dire” – a trial within a trial, conducted in the absence of the jury – to see whether his evidence could be admitted. Lovers of legal gobbledegook, incidentally, relish a voire dire to see if a witness is peritus.

It gradually emerged that Mr Ager’s credentials were not quite as impressive as his CV had suggested. He couldn’t remember if he even had any ‘A’ levels, although he did remember sitting some. Instead of doing courses or attending lectures, he said he had learned on the job, or, as he put it “from my environment.”

There is apparently just one book on carbon credit frauds (Marius-Christian Frunza’s Fraud and Carbon Markets: the Carbon Connection Routledge 2013, £120.00, since you ask): he had not read it. As the judge put it:

“… someone who purports to be an expert in a particular field has not read what I think is the only known publication in that field.”

Mr Ager had given a lecture to some police officers from the City of London Police in 2012, and another in 2014. As a result of these two presentations he described himself, impressively, as “an associate of the UK Economic Crime Directorate’s Training Centre for Economic Crime and Fraud.” The City of London Police Force does indeed have an Economic Crime Directorate which, without burdening this blog with organograms, can be said to have a national co-ordinating function. On the other hand it was stretching it a bit to say that delivering two talks, the most recent one 5 years earlier, made him an “associate” of the Directorate.

The expert’s duty to the court

In the end, it was not his lack of formal training or book learning that was Mr Ager’s final undoing. It was that he showed a complete lack of understanding of the duties and responsibilities that the courts now – in principle if but not always in practice – require of expert witnesses.

The most important of those duties are now set out in Rule 19 of the Criminal Procedure Rules, and include (for example):

A duty to give an “unbiased and objective” opinion;

A duty to give details of any literature or other information which the expert has relied on in making the report;”

A duty to include within his report such information as the court may need to decide whether the expert’s opinion is sufficiently reliable to be admissible as evidence;”

There are many others.

The point is that an expert should not be a “hired gun” acting for one side, but an objective and unbiased witness who owes a primary duty to the court, which “overrides any obligation to the person from whom the expert receives instructions or by whom the expert is paid.”

Mr Ager said that he had read the Criminal Procedure Rules and the CPS “Guidance Booklet for Experts” (which explains these duties in much more detail) but there was very little evidence that he had digested their central principles.

Shortly before the trial, he rang up the defence expert, who happened to be Professor Frunza who wrote the book which Mr Ager had not read. There are rules about experts talking to each other in this way and, needless to say, he broke them. Amongst other things, Mr Ager told him:

* That several people had died as a result of losing their pensions.

There was, as the judge observed, no evidence of that having happened.

* That there was a police report that spoke of money being spent on Ferraris, Lamborghinis and an Aston Martin.

There was not.

* He spoke of giving evidence as being an ‘horrendous environment’ in which ‘the last thing you want to do I guess is claiming, finding out that what you are defending is someone who has taken someone’s life savings etc’.

* He said that “the last thing you want to do is to be called to court to give evidence because if the court reporters got hold of it, something like that, you know it could be reported, if the industry itself grab hold of it…..”

According to the trial judge (HHJ Lorraine-Smith):

“… it seems likely that Mr Ager was keen that his evidence should not be challenged and he felt threatened by the prospect of a far more impressive expert appearing in an area of expertise in which he hoped to continue making a living.”

It was this disgraceful telephone call, rather than simply Mr Ager’s absence of qualifications, which finally led to the prosecution deciding that they could no longer rely on Mr Ager as an “objective” expert. Without his evidence they could not continue with the prosecution, and they had no choice but to drop the case.

Quite apart from Mr Ager, neither the CPS nor the police emerged particularly well from the case. Mr Ager said, for example, that there had been no contact between him and the CPS until a week before the trial, something which he said was “not unusual.” As for the police, not only did they take Mr Ager’s boastful CV at face value, at times they even came close to writing passages of his statement for him, although the case collapsed before the officer’s behaviour – described as “rather too proactive” by the judge – could be fully investigated.

In that case a possible injustice to the defendants was averted, albeit at the considerable cost of doing a great injustice to those who had lost money and deserved a competent and professional investigation and prosecution of those they believed to be responsible.

The most alarming thing about the case, though, is not that Mr Ager was finally discovered to be an unclothed emperor, but the deference with which he had been treated in earlier cases, many of which had resulted in convictions. No-one seems very sure how many others there may have been. Mr Ager’s own estimate varied between about 20 and up to 50.

For all the forensic expertise deployed on both sides in all those cases, Mr Ager was able to forge a career for himself, and it seems quite a well-paid one, as the “go-to” expert in carbon credit frauds. He was not rumbled until he was cross-examined by Narita Bahra QC in the latest case.

I am afraid the only possible conclusion to be drawn from that is that the safeguards the criminal justice system ought to have against the admission of unreliable expert evidence cannot be working very well.

*** *** ***

Inexpert, over-confident and occasionally plain dishonest “expert” witnesses have been one of the most potent sources of miscarriages of justice for generations.

Sir Bernard Spilsbury: a celebrity pathologist

In the early years of the twentieth century Sir Bernard Spilsbury, the Home Office pathologist, made an almost inevitable appearance in every major murder trial. Tall, handsome and often dressed in top hat, tails and spats, and usually with a carnation in his lapel, judges and juries adored him.

One of his most famous cases was the 1922 trial of the Hay-on-Wye solicitor Major Armstrong for poisoning his wife with arsenic. Spilsbury had conducted the post-mortem and gave, as usual, damning evidence for the prosecution. It was strongly challenged by the defence. The details need not concern us here; the striking point is the star-struck way in which Mr Justice Darling, admittedly a notoriously unfair judge, reminded the jury of Spilsbury’s evidence:

Do you remember Dr Spilsbury, do you remember how he stood and how he gave evidence? Did you ever see a witness who more thoroughly satisfied you that he was absolutely impartial, absolutely fair, absolutely indifferent as to whether his evidence told for one side or the other …?”

Whether or not he was right in the Armstrong case, the judge’s assessment of Spilsbury was wide of the mark. He could be exceptionally partisan and grossly unfair.

In the year after the Armstrong case Spilsbury’s evidence helped to convict a young corporal, Albert Dearnley, of murdering his best friend by suffocation. Dearnley rather unconvincingly claimed that he had died during a rough game of Cowboys and Indians, an explanation that the jury clearly found ridiculous. Spilsbury suspected that he had in fact been accidentally asphyxiated during consensual sado-masochistic activity, but, shockingly, he kept his suspicions to himself, believing that the defendant was a sexual pervert who deserved his fate. Dearnley came within 48 hours of being hanged: indeed the Home Secretary had initially refused a reprieve and only changed his mind after the personal intervention of the prison governor who had read some of his personal correspondence. Even during his lifetime many in the medical profession were suspicious of Spilsbury’s methods as well as jealous of his celebrity status. Since his death – a lonely suicide in his laboratory with coal gas hissing from his bunsen burners – these suspicions have only multiplied.

Since Spilsbury, expert evidence has continued to be responsible for a steady stream of wrongful convictions. Bogus, dishonest, partisan and incompetent expert witnesses have remained a problem that the criminal courts struggle to deal with.

Expert conmen

Gene Morrison, for example, was an out-and-out conman whose only qualifications were certificates bought from  He posed as an expert psychologist in court cases over nearly 30 years before he was uncovered and eventually gaoled. Such very limited expertise as he acquired to perpetrate his frauds came from watching videos of 1970s Open University TV broadcasts.

Barian Baluchi – who also “qualified” by buying degrees online – earned at least £1.25M as a bogus Harley Street doctor. A steady stream of that income came from writing psychiatric reports for Immigration Tribunals (although he also got £150.00 for removing a wart from a patient’s penis, an unusual task even for a properly qualified psychiatrist). He too ended up in prison.

These were out and out frauds. Nobody spotted them for years.

But even genuine experts can be just as dangerous when they allow their independence to become compromised or when – as they often do – they go beyond their proper area of expertise.

Sally Clark

Possibly the most notorious miscarriage of justice uncovered this century was that of solicitor Sally Clark, who was convicted of murdering her two children. One of the main prosecution witnesses was Prof Roy Meadow, at the time regarded as perhaps the country’s most distinguished paediatrician.

Part of the case against her was based on misunderstood statistics, as articulated by Prof Meadow. The chances of one child dying from SIDS (“sudden infant death syndrome”) was said to be 1 in 8,543. So, claimed Prof Meadow, the chances of two children randomly dying from SIDS in the same family were “1 in 8,543 times 1 in 8,543” which made 1 in 73 million. To bring the point home to the jury he likened it to backing an 80 – 1 winner in the Grand National in four consecutive years.

(In fact, using Prof Meadow’s own flawed approach, the statistical chance that Mrs Clark was a double murderer was far more remote even than the so-called “73 million to 1” chance that her children had died of natural causes. )

Prof Meadow was no charlatan. Yet for all his eminence his evidence on statistics was junk science which should never have been allowed in court. It was subsequently condemned by the Royal College of Statistics as a “misuse of statistics.”

Despite recognising that the statistical evidence was unsound, Sally Clark’s conviction was originally upheld by the Court of Appeal. It was not until her case was taken up – for free – by the family law solicitor Marilyn Stowe that previously undisclosed blood test results came to light which suggested a natural cause of death. Only then did the Court quash her convictions.

Mrs Clark tragically died not long after her release her life destroyed by the combination of losing her children and then being wrongfully convicted and imprisoned for murdering them.

The Criminal Procedure Rules

It was because of cases like these that the Law Commission decided to examine the law on the admissibility of expert evidence in criminal cases. Its 2015 report recommended that there should be a statutory test of admissibility for expert evidence which would prevent the admission of expert opinion evidence which is not sufficiently reliable to be admitted.” Like many Law Commission recommendations this sensible suggestion was not taken up by the Government, and the admissibility of expert evidence is still ultimately governed by the common law.

The 2015 Criminal Procedure Rules and their associated Practice Directions aimed to tighten the rules so that unsuitable experts would be easier to spot.

Unfortunately, the rules do not seem to be working. Sulley was not an isolated case. It bore a number of striking features in common with a Serious Fraud Office prosecution called Pabon [2018] EWCA Crim 420 which was heard by the Court of Appeal last year.

Another dubious banking expert

The expert in question in that case was a man called Mr Rowe, who also gave evidence about banking, in a trial which concerned the fixing of short term interest rates for the personal advantage of individual bank employees.

Mr Rowe was asked in particular:

“… to provide assistance with STIR [Short Term Interest Rate] trading … DV01 [The change in Dollar Value of a contract or book resulting from a 1 basis point move in the interest rate – a measure used by traders to assess risk], curves, stub, resets, risk and the importance of tiny movements in Libor…..”

Mr Pabon and several of his co-defendants were convicted.

In the case of other defendants there was a hung jury, and a retrial followed.

At the retrial Mr Rowe’s status as an impartial expert fell apart.

It emerged that parts of his original report had not even been written by him but by others in his firm, something which he had not disclosed at Mr Pabon’s trial.

It got worse. It turned out that at the original trial he had discussed aspects of his evidence with others in an overnight break while giving evidence, despite having been given a strong warning not to do so. He was asking for help because he doubted his own expertise on the very matters on which he was being questioned. Needless to say he did not reveal this to anyone. According to Lord Justice Gross, Mr Rowe “signally failed to comply with his basic duties as an expert.”

“… he did not inform the SFO, or the Court, of the limits of his expertise. He strayed into areas in his evidence (in particular, STIR trading) when it was beyond his expertise (or, most charitably, at the outer edge of his expertise) …. In this regard, he was no more than … an “enthusiastic amateur”. He flouted the Judge’s admonition not to discuss his evidence while he was still in the witness box. We take a grave view of Rowe’s conduct.”

“… this case stands as a stark reminder of the need for those instructing expert witnesses to satisfy themselves as to the witness’ expertise and to engage (difficult though it sometimes may be) an expert of a suitable calibre.”

Despite all this the Court actually upheld the convictions from the first trial because the areas in which Mr Rowe had given evidence were not, in the context of that trial, the Court felt, particularly controversial.

Not our fault

The SFO conducted an internal review and claimed to have “learned lessons” from the case, and from the other case in which they had instructed him. You may not be surprised to hear that the principal lesson it learned was that the SFO itself was blameless:

Rowe’s conduct resulted from a failure of integrity on his part rather than a failure of SFO policies or procedures.”

The tip of an iceberg?

The most serious problem is that “experts” like Ager and Rowe are unlikely to be isolated aberrations; they are just the most recent ones that got found out. Both of them gave evidence in cases for years without anyone noticing. How many other “quacks, charlatans and enthusiastic amateurs” have corrupted justice by giving their evidence undetected and perhaps even unchallenged in court? We have no idea, but the probability is that those who have been detected represent the tip of an iceberg.

A solution?

Nothing seems to change. The English and Welsh criminal courts have always been very poor at weeding out these menaces. When one is found, judges denounce individuals. Law Commission and Select Committee reports are written, and are then left to gather dust. Rules which look good on paper are introduced but not observed in practice. Prosecutors and police go through the ritual of apologising and claiming to have learned lessons, but then the same mistakes are then made again. 

This is not, ultimately, a problem just of money, although as the Lords Committee Report made clear, lack of money is greatly increasing the risk that disasters will take place again.

An even more fundamental problem is that for some reason our criminal justice system still seems to find it extraordinarily hard to detect the bogus or incompetent experts. I can think of no magic solution to deal with the problem, although perhaps full implementation of the Law Commission’s recommendations might help.

In the meantime it would be a good start if advocates, trial judges and the Court of Appeal were to scrutinise the credentials of expert witnesses with a great deal more care than has traditionally been the case, and to insist that the Criminal Procedure Rules are always properly observed.

Author: Matthew

I have been a barrister for over 25 years, specialising in crime. You may also have come across some of my articles I have written on legal issues for The Times, Standpoint, Daily Telegraph or Criminal Law & Justice Weekly

5 thoughts on “Expert witnesses: a crisis in the criminal courts”

  1. Dear Sir,
    Robert Black QC FRSE – Professor Emeritus of Scots Law in the University of Edinburgh and best known as the “Architect of the Lockerbie Trial” — has written : “The Lockerbie trial is the most disgraceful miscarriage of justice in Scotland for 100 years. Every lawyer who has read the judgment says ‘this is nonsense’. It is nonsense.”
    your readers may be interested to learn about the Lockerbie witnesses and experts.
    Here are a few stories:
    Lockerbie — The Eyewitness Evidence Against Megrahi : Exclusive Q&A with Professor Tim Valentine
    Lockerbie — The Eyewitness Evidence Against Megrahi : Exclusive Q&A with Pr Elizabeth Loftus
    Lockerbie Case Review — Key Witness Tony Gauci Was Unreliable
    These stories were posted on the Intel Today blog.
    Dr Ludwig De Braeckeleer

  2. I am a Chartered Surveyor of 50 years standing who acts as an expert witness, I have taken formal (Bond Solo) training and have CUBS accreditation.
    I sometimes meet fellow surveyors who have no such training or accreditation and have never or rarely given evidence in Court.
    They have passing knowledge of CPR Pt.35, but in little or no depth….they are open to embarrassment when cross examined.
    Once, my opposite number, in ignorance, admitted in email that his report had been influenced and manipulated by his instructing solicitor !

  3. A lucrative source of income beckons to me, but alas, my personal area of expertise is in the developmental anatomy of the musculature of the laboratory mouse and variants thereof. I am published in Nature no less doing this.

    However the chances of this being needed in a trial are vanishingly small, another career move dashed. I must rack my brains to come up with something else. I do developing mouse skeletons as well (it was necessary in the Nature paper to certify no changes and I did that). Not very warm though.

    I simply must try harder.

    As for your article Matthew it was fascinating. The ideological and money driven destruction of the Forensic Science Service is nothing less than an absolute travesty. I have known excellent departments and institutes be destroyed by ignorance and empire building but the FRS was my first national organisation. It shocked me.

    1. Thank you Peter, and don’t lose all hope of becoming the Spilsbury of the rodent world …. No, that doesn’t really work for lots of reasons, but you’d be surprised how many exotic areas of knowledge are sometimes needed in court! I think lapine ophthalmologist is the most unusual I’ve had.

  4. ‘The point is that an expert should not be a “hired gun” acting for one side, but an objective and unbiased witness who owes a primary duty to the court’.

    And that’s exactly what I was told by the barrister and solicitor who put me up as an expert witness in a civil case. The barrister emphasised the point: “You must not behave as American expert witnesses do (at least as represented on TV)”.

    My wife’s advice was severely practical: “Be sure to wear a Cambridge college tie”.

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