Did Lucy Letby’s Defence Team Collude in a Guilty Verdict?

Unmasking Lucy Letby, by Jonathan Coffey and Judith Moritz

Guy de la Bédoyère has read a recent book by two BBC reporters about the Lucy Letby case. Here he reviews the book and comments on some of the wider issues it raises.

The Lucy Letby case has been one of the most controversial in recent years. The extent of the tragedy unfolding at the Countess of Chester Hospital around a decade ago involving the deaths of seven premature and vulnerable babies has provoked some of the strongest reactions and opinions in Britain.

A recent Panorama film (Lucy Letby: Who to Believe?) presented by the BBC reporters Jonathan Coffey and Judith Moritz covers the complexity of the case, the decisive role expert witness opinion played in the absence of unequivocal circumstantial evidence for Letby’s guilt, and the decision of the defence not to bring expert witnesses to court. Nonetheless, some critics of the film missed the point. A Guardian review criticised the Panorama for failing to provide evidence to suggest there is a “compelling alternative to the events set out by the prosecution”.

It’s not the only programme by any means to have questioned the quality of the evidence. The Guardian’s Lucy Mangan called ITV’s Lucy Letby: Beyond Reasonable Doubt? one of most meticulous documentaries in years:

The makers do not dwell on why Letby’s team put forward such a minimal defence. … But, by the end of this considered, brilliantly cogent hour you cannot help but feel that at the very least Letby’s conviction is unsafe.

By comparison, Coffey and Moritz argue that the evidence is not compelling either way.

I contacted the Panorama reporters about my own experiences. Jonathan Coffey replied, interested in my points, and sent me a copy of the updated 2025 paperback edition of the book he and Judith Moritz have written about the case (Unmasking Lucy Letby), inviting me to comment. It is one of the best written and structured books about a legal case I have ever read. The case is described with forensic clarity, lucidity and fairness. The complex evidence is covered with frankness and balance. The different ways the evidence has been treated, validated, supported and disputed are handled objectively:

We have seen experts from both sides of the debate make claims that are flawed and untrue. The real culprit – if there is one – is our system for determining truth and justice, and the way in which expert evidence is sought, interrogated and ultimately used to send people to prison. (p. 503)

Coffey and Moritz’s book does not attempt to exonerate or condemn Letby. Nor does it recreate a narrative version of events based on either the prosecution or defence case. This makes it quite unlike, say, Ludovic Kennedy’s 10 Rillington Place which set out to, and achieved, a posthumous pardon for the alleged murder by Timothy Evans of his wife and daughter by arguing that the serial necrophiliac murderer John Christie, who lived in the same building, was responsible.

There are aspects of the evidence of the case and Lucy Letby herself that we still don’t know. This feeling that there is a missing piece of the jigsaw that no one has seen is a feeling we both have. (p. 502)

In history and archaeology definitive circumstantial evidence is usually lacking. Variant and conflicting ‘expert’ opinions are substituted and narratives manufactured out of the minimal evidence available. Experts in such fields get away with that because it is unlikely the definitive evidence will ever emerge either to confirm their views or expose them as nonsense.

During Covid the extent to which expert opinion was being used to create an aura of certainty became obvious. It was clear that few, if any, had any real idea of what was going on. Battalions of ‘experts’ promoted hypotheses dressed up as ‘The Science’ or were casually interpreted as such. Scientists are human beings, and they have a habit when definitive evidence to explain causation is lacking to say instead what they would like to be true, especially in a public forum.

In some cases, they’ve made a leap from hypothesis to causation, almost in the way the causation of a miracle is explained in a religious context. This is completely different to, say, a solar eclipse where causation can be explained with indisputable evidence. The distinction is critical, but it’s often overlooked and the principle of testing scientific hypotheses to destruction is easily forgotten. In the remoter past, figures of religious authority made that leap from religious hypothesis to causation. Society was accustomed to deferring to them. In many ways we are behaving in the same way but with a new type of priesthood.

1. Lucy Letby’s personality

Lucy Letby’s personality and background are explored extensively in the book. She appears to have been an innocuous individual, which in the context of the case appears incomprehensible. The authors go to town trying to find secrets or hidden aspects of Letby’s past and by their own admission get nowhere. That is not the same as there being nothing to find; if there was, they did not uncover it.

For nine years I taught girls at a secondary school in Lincolnshire. The description of Letby would have been good for as many as 75% of them. The vast majority were, like Letby, well-behaved, conscientious and meticulous. Like her, they sought praise (e.g. p. 409), avoided being conspicuous and weren’t vocal in class. In my experience, this is the public face many girls put on.

Sometimes at parents’ evenings it would emerge that the girls were different people at home. Therefore, it would be easy to read into Letby’s manner in court aspects of her personality that probably aren’t true and helps explain the loyalty of her friends and parents.

In Letby’s notes, she castigated herself for the loss of the babies (e.g. p. 343). In my experience of teaching girls they are, for whatever reason, often prone to criticising themselves, believing that they are responsible for the welfare of others and that their actions or negligence might inadvertently cause harm.

The book discusses how the teenage Letby was sometimes seen as “stony and cold” and “socially reserved” (p. 12). This lack of emotion and passivity in court and her calmness in crises have excited comment as suspicious, and indicative of her being “unfeeling and odd” (p. 397) but that doesn’t acknowledge how differently people can react to crises and tragedy. Much to the astonishment of his parishioners, in 1958 my late father-in-law, a priest, took the Sunday service as usual, despite having discovered in the early morning that his infant eldest daughter had succumbed to a cot death overnight. It was his way of coping.

This doesn’t mean those who believed Letby was peculiar in her behaviour are demonstrably wrong; merely that they’re relying on a very narrow idea of how one should behave in the aftermath of a tragedy, most likely to be aired by people who have not experienced one. None of the witnesses to Letby’s behaviour following an infant’s death have any idea how she might have behaved in private. Only her closest friends and family might be able to form a judgement, and it is noticeable that they have supported her throughout.

Nonetheless, Letby’s interest in being present at tragedy and even choreographing the aftermath is a matter of interest and I will deal with it at the end.

2. Scientific knowledge and understanding

Coffey and Moritz discuss how prone to dispute scientific opinion is, as opposed to scientific fact. The book’s concluding remarks on pp. 503-4 encapsulate the unsatisfactory consequences of relying on disparate and selective scientific opinion and the dizzying array of contested points. The key factor is the lack of a smoking gun.

In Chapter 10 the explanation of how expert scientific opinion was used to incriminate Letby could go further. There is now a huge desire to rely on ‘The Science’ to understand many phenomena that affect our lives. Scientists act as gatekeepers through whom ‘The Science’ is transmitted to the wider public. The implication always is that science has a degree of objectivity that gives it a decisive advantage over other methods of inference or deduction. Science thus becomes the preferred source of explanation, especially in the absence of unequivocal circumstantial evidence, and is allowed thereby to take precedence in that vacuum of alternatives.

Part of the problem is that scientific understanding and method are not automatically intuitive, even to scientists. Since scientists are human beings, when confronted with information and data that relies on interpretation and selection (unlike, say, DNA evidence, though even that relies on an evaluation of probability), some are easily inclined to drift from scientific deduction into stating that they ‘believe’ something, implying that it is fact. To do this, they use their status as scientists and self-confidence to bolster and underpin the credibility of that belief.

Having taken a position, some are then reluctant to back down and expect deference from others, especially the ‘public’. Often, the scientists most effective at blurring science and belief in a public context are also accomplished performers; that is why they are so successful in pushing their opinions as fact. Some undoubtedly seek out the public arena where acceptance of their views affirms their sense of their own importance. For those who are retired, a public arena enables them to cling on to the status and authority they once enjoyed at work.

The drift from true science to belief is most likely to happen when there is a lack of unequivocal evidence for an event or phenomenon. In Letby’s case the absence of DNA or CCTV evidence, or being caught in the act, is crucial. Had any of this existed, there would have been no need to pursue the ambiguous and debatable ‘scientific’ evidence in such laborious detail. It was wheeled out to act as a substitute but struggled to produce definitive explanations, complicated by the babies being premature.

The Letby saga has lasted so long because the nature of the scientific evidence has subsequently been exposed for being far more inconclusive than it was originally depicted as in court.

We saw this constantly throughout Covid. The public demanded certainty, and expected it from scientific ‘experts’, but were disoriented by the contradictory and incompatible hypotheses being depicted as if they were definitive explanations for causation. (First, the experts told them masks were useless, then indispensable.) In the longer-term the truth, viz., that the experts almost without exception were out of their depths, became more widely realised.

The consequences of this are significant because scientists in such contexts are addressing people whose understanding of science is limited, or even nil, but who want to believe ‘The Science’ because it offers a mirage of certainty. Juries are particularly vulnerable, and the potential consequences more serious than in everyday life.

3. The evidence in court

Throughout the writing of this book, numerous experts have told us that the adversarial use of experts by prosecution and defence often does little to uncover the truth. Experts vary in quality. The best ones aren’t always available. Some are too timid to gainsay groupthink. Others tell their paymasters what they think they want to hear. (p. 503)

Because the circumstantial evidence is weak and disputed, the prosecution case relied on carefully curated and selected (by the prosecution) expert scientific opinion instead, and thereby making the leap to causation. The central part of the prosecution case was that the malicious injection of air by Letby had caused fatal air embolisms in all or most of the seven babies who died. No evidence was found that directly implicated her. “The air embolism theory turned out to be one of the most controversial aspects” of the case, say the authors (p. 247), not least because one of the authors of the 1989 paper that described the phenomenon, Professor Shoo Lee, announced in 2025 at the head of a panel of experts that there was no evidence of air embolism in the instances where it had been claimed, and that there was no evidence of malfeasance in any of the babies’ deaths.

Coffey and Moritz describe how the principal prosecution witness, Dr Dewi Evans, put himself forward to the police in the first place. His judgements became the foundation of the prosecution case in the absence of definitive evidence. “His opinions shaped much of the prosecution case,” say the authors. The prosecution was effectively saying that because the experts they had assembled believed Letby was guilty, and in the absence of proof that she wasn’t guilty, therefore she must be. Not exactly beyond reasonable doubt.

It usually transpires under such circumstances that there are almost unlimited variant opinions based on interpretation and different specific professional experiences, compounded by posturing, a desire to adopt a position to have a seat at the table, a reluctance to lose face by backing down and so on. They cannot all be right. Obviously most or all will be wrong; the trouble is deciding which.

On p. 215 the book summarises how the defence team’s own expert, Dr Mike Hall, supplied his opinions challenging the prosecution’s case. However, the defence chose not to use him or any other expert witness in court. Only a hospital plumber was called to attest to hygiene issues caused by sewage problems. The authors conclude that ultimately this decision was inexplicable and symbolised the flawed nature of the trial.

If the defence team, led by Ben Myers KC, had acted differently, then the jury might have been confronted by the challenging prospect of deciding which expert opinion to believe, but without the training or background to be able to do so. It would have been far harder for the jury to have come to unanimous or even majority decisions because it would have been clear to jurors that both the prosecution and defence were making some claims that were “flawed and untrue”. The jury would then have been confronted with a more nuanced portrait of the reality which is that:

• The circumstantial evidence for Letby’s guilt is inconclusive and subjective or at worst, non-existent, and
• The expert scientific/medical opinion is equivocal because the medical evidence for the babies’ deaths is inconclusive too (see p. 465)

The concluding chapter’s detailed comments on Letby’s new barrister Mark McDonald’s ‘14 Experts’, on the findings they announced in February 2025 (now before the Criminal Cases Review Commission) in which they refuted the claim there was evidence she’d committed murder, and on subsequent criticisms of those findings, only go to show further how variable and flawed expert opinion can be. The Guardian quoted the report’s conclusion:

“There was no medical evidence to support malfeasance causing death or injury in any of the 17 cases in the trial,” the report concludes. “Death or injury of affected infants were due to natural causes or errors in medical care.”

Coffey and Moritz discuss these revelations and the criticisms made of them, suggesting that in certain respects they are at least as flawed as the prosecution’s case. But the ‘14 Experts’ had raised more doubt about how a case can rely on any scientific opinion, especially to convict someone to life in prison with no prospect of release.

4. Evolutions in the narrative

Cases based on expert opinion involve creating narratives in the absence of an uncontested narrative of events. After volunteering himself as an expert witness, in 2017 the retired Dr Dewi Evans produced reports for “around 30 babies” whose records were sent to him by the police. “They bear a pretty close resemblance to what Letby was tried for and convicted of,” the authors say (p. 244).

In a Telegraph article produced to coincide with a new Channel 4 documentary about the case transmitted on September 29th 2025, McDonald stated that “Dr Dewi Evans has published no papers, written no books, and is not even a neonatologist… but a paediatrician and one who had not practised for 15 years”.

On p. 303 the evolution of Evans’s opinions (which “shaped much of the prosecution case”) is discussed. The authors describe how he defended his changing opinions because he received “additional information”. He produced eight reports alone just for one of the babies (p. 253). Yet, he had asserted previous opinions with confidence, even though by changing his view he exposed the original opinions as no longer so certain. It does not seem to have occurred to anyone at the time that his latest opinion might also become obsolete in the light of new information. He was not the only prosecution expert witness to change his mind, according to Coffey and Moritz.

Evans was, arguably, conscientiously sticking to the scientific method. However, the book suggests that he did not readily distinguish between science and belief. The authors comment: “As for the idea that Letby could be innocent – it’s not a thought that Evans even entertains” (p. 246). They describe him as arguing that Hall had “misunderstood his [Hall’s] role in the case – opting to play the role of Letby’s advocate rather than an impartial expert”. Yet the authors quote Evans on the same page (p. 267) saying “she bloody murdered those babies”.

Coffey and Moritz call this a striking claim for someone whose impartiality was constantly questioned in court. In the Panorama film, when confronted with this, Evans said of the experts who dispute his point that “perhaps they don’t know as much as they think they do” (or words to that effect). It did not apparently occur to him that those other experts might equally have made the same claim about him.

The authors suggest that Evans’s certainty of Letby’s guilt underpinned everything he said. Even though his scientific interpretations changed, they always began with, or led him to, his belief in Letby’s guilt. Instead of each of Evans’s opinions being tested to destruction they were presented in court as definitive explanations.

When tackling the early scepticism about the trial’s outcome in 2023, the book quotes in the notes a now-defunct website called Science on Trial as saying:

Scientifically, the case against Ms Letby has not been proven. The major scientific evidence presented to the jury amounted to two blood tests and x-rays. All the other evidence relies on significant interpretation by expert witnesses. … Questions should be asked as to how such minimal medical evidence can be used to convict a person of murder and attempted murder, least of all when the autopsies do not correspond with the alleged cause of death.

The website was not the only source starting to question what had taken place in court involving scientific expert opinion and the implications for the accused.

5. Eyewitness evidence

On p. 330 it’s stated that there is “no reason to doubt” eyewitness evidence of Letby’s whereabouts. I disagree with this. There is every reason to doubt such evidence. Indeed, it should be doubted, and at the very least queried:

• I can count among my friends a retired US state prosecutor. She told me that the most important lesson she had ever learned in her long career was the chronic unreliability of eyewitness testimony.
• My experience of keeping a detailed diary while working as a teacher demonstrated to me than unless details of persons, times and places are recorded immediately and in detail it is impossible within 24-48 hours or even less to be certain of any of the detail or sequence. Episodes are easily blurred, and so are the identities of the people involved.
• Without any corroborating evidence (such as the exceptional instance of one of the baby’s parents being able to verify the time at which she saw Letby with a baby from a 9.11pm mobile phone record), any claim to have seen Letby anywhere at any time should have been challenged and treated as potentially unreliable.

6. A Misadventure?

Coffey and Moritz suggest subtly that the trial was a misadventure even if it led to the verdict that so many involved desired. They state that in their view something is manifestly missing from the whole story. Whether the trial resulted in a miscarriage of justice is another consideration altogether.

One topic discussed in the book is especially striking: Letby’s interest in being present during the dramatic and tragic episodes when babies grew seriously ill with some of them dying. She enjoyed the praise from parents and colleagues and wished to be a proactive and vicarious participant in the parents’ grief and turmoil by manufacturing souvenirs for them and researching the families. This taking of control – the “saviour complex” – is discussed on pp. 399 and is developed on pp. 405.

Nonetheless, it’s an enormous stretch to jump from this sort of behaviour to killing babies to gratify herself; the book says it is “at least possible” but queries whether it is likely (p. 409).

The authors do not mention, perhaps wisely, that there’s a technical possibility that if Letby is guilty of anything (and the book shows that her guilt in any capacity is not cut and dried at all) it might be of seeking to create situations which she could revel in and preside over, but which did not have killing the vulnerable babies as the prime purpose; rather, their deaths might have been an unintended consequence of her reckless interference in their care.

Had Letby been employed in another walk of life she might have sought similar gratification but without such devastating outcomes (no doubt such behaviour usually goes unnoticed in most other contexts for that reason). This would certainly help explain a) her denials since she could sincerely believe she had not set out to kill the babies, and b) why most of those concerned did not die.

This hypothesis of course is as vulnerable to the lack of a smoking gun as is accusing Letby of deliberately murdering the babies. It would also need to be tested to destruction but now it is unlikely that will ever happen. Nor is there likely to be any evidence to substantiate it any more than there is for deliberate acts of murder.

Either way this shows that the inconclusive circumstantial evidence means alternative hypotheses are possible. These also includes the possibility that Letby is innocent and is the unfortunate victim of a tragic series of coincidental deaths which took place in a dysfunctional hospital. 

7. Conclusion

It is clear from the book that Coffey and Moritz believe that any objective assessment of the available evidence should lead to concluding for the moment the case is not proven either way. Their observation that Letby is neither demonstrably guilty nor demonstrably innocent is piercing. There are too many plausible grounds for multiple interpretations of the evidence, in the absence of definitive circumstantial evidence. Far too much depends on probability, subjective assessments and belief, not rational deduction, as the authors argue. There are also worrying signs of the ‘Establishment’ wishing to suppress any criticism of the guilty verdict, as is usual in high-profile cases. This is why miscarriages of justice can take decades to expose.

The section discussing why expert witnesses were not called in Letby’s defence, though the prosecution witnesses were challenged and cross-examined by the defence, is one of the most enigmatic and well-drawn aspects of the whole book. The secrecy and confidentiality, which the authors describe because it prevented them from finding any answers, left me wondering whether the unfortunate conundrum facing the police and the legal teams was that they knew (or believed they knew) Letby was guilty but that the case was going to be extremely difficult to prove. The resultant trial appears almost to have been choreographed to ensure a guilty verdict.

Of course this is an apparently preposterous suggestion. But it is virtually the only way to explain the defence’s decisions, which Coffey and Moritz argue were otherwise negligent or inexplicable. They contrast this with Ben Myers KC’s vigorous and animated defence at the second trial concerning a single baby, which only emphasises that what happened at the first trial makes no sense.

The authors argue that all this means there is manifestly something missing no-one has yet spotted or has access to. There is also their concern that a system which relies on subjective expert opinion rather than substantive evidence is an unreliable basis for sending someone to prison.

One cannot of course overlook the wretched fate of the parents of the babies, whose trauma has been stretched out now over a decade. Coffey and Moritz go to considerable lengths to take account of that and with enormous sympathy; but they evidently feel the saga remains unresolved and that for everyone’s sake it needs to be resolved.

If you are interested in the Letby case, do read Unmasking Lucy Letby regardless of whatever position you already hold, or even if you hold no position at all. The book has implications for the Letby case, and for understanding both the way expert opinion is used in British courts and the role of expert opinion in modern society in a far wider range of contexts.

Star Trek may seem an odd place to end, but Spock’s observation in one episode is enduringly relevant:

There must be an explanation captain. We simply haven’t discovered it yet.

I think that sums up this remarkable book.

Guy de la Bédoyère is a historian and writer with numerous books to his credit. His latest book is The Confessions of Samuel Pepys. His Private Revelations (Abacus 2025).