#LucyLetby: Can you imagine going to jail on the basis of a coin toss? Try this for a thought experiment... Heads: Dr Dewi Evans becomes lead medical expert investigating the deaths and collapses at the Countess of Chester neonatal unit. Tails: Professor Shoo Lee gets that job. The babies are the same. The records are the same. The deaths and collapses are the same. Only the reader of the medical notes changes. In the first world, the records are interpreted as evidence of a series of deliberate attacks. A nurse becomes the subject of a murder inquiry. She is convicted and sentenced to die in prison. In the second world, a leading neonatologist and an international panel read the same clinical records and find no medical evidence of deliberate harm. They identify poor resuscitation skills, missed diagnoses, inadequate supervision and a unit struggling to care for its sickest babies. The question becomes how to make the unit safe, not whom to convict. Professor Lee went further. He said that if this had happened in a Canadian hospital, the unit would have been shut down. And in July 2016, long before Lee's review, the hospital did downgrade the unit and stop admitting its most premature babies. So the clinical safety concerns were hardly imaginary. But the two readers are not interchangeable. Lord Justice Peter Jackson had previously described a report written by Evans in an unrelated family case as "worthless", criticising its "tendentious and partisan" opinions. Lee, meanwhile, co-authored the 1989 paper on air embolism in newborns relied upon by the prosecution. He says his research was misinterpreted. His international panel of 14 specialists from six countries reviewed all 17 cases and found no medical evidence of deliberate harm, attributing the deaths and injuries to natural causes or poor medical care. So the question is not simply which expert we might prefer. It exposes something significantly more disturbing. How can substantially the same clinical records support interpretations so far apart that one leads to whole-life prison sentences while the other points towards shutting down the entire neonatal unit? And if expert analysis can yield conclusions so vastly different, how can we be confident that a jury, without the benefit of the second interpretation, was able to establish beyond reasonable doubt that any crimes had been committed at all? This counterfactual does not, of course, prove Letby innocent. It exposes a vastly deeper problem. It is one thing for experts to disagree about who may have committed a crime. It is quite another for them to disagree completely about whether a crime had been committed in the first place. If the existence of alleged crimes can depend so heavily on which expert is appointed to interpret the clinical evidence, what does that tell us about the safety of convictions built upon those interpretations? The foundations of a whole-life prison sentence deserve to rest on something vastly more secure than an interpretation that reflects the choice of the toss of a coin.