The prosecution mounted an “absolutely rigorous” case against Keran Henderson that excluded all possibility of death by natural causes, legal sources have told The Times.

Lawyers are privately worried that the view is gaining ground that the mother of two should not have been prosecuted after two jurors questioned her conviction for violently shaking Maeve Sheppard to death. But one legal source said: “This was not one of those troubling cases where you have banks of experts teamed up on each side who completely disagree with each other. The prosecution would never have allowed this to go ahead if that had been so.”

The strength of the prosecution’s position was borne out by its being able to bring forward four expert medical witnesses against one for the defence, the source said. “Because there was no supporting evidence and the case relied entirely on expert evidence, the prosecution [considered] every possible natural cause of death with extreme thoroughness. No stone was left unturned.

“Of course it was an extremely upsetting case because Mrs Henderson was a woman of good character who was very distressed throughout the trial. So it is understandable if jurors are upset.”

The jurors’ confusion in such cases might be cleared up if they were given written summaries of the evidence and arguments, the source said. The foreman of the jury had requested a transcript, but that had been refused on the ground that it would take too long to produce.

Defence lawyers argued that the baby sustained her injuries during a seizure while having her nappy changed. But the source said there was compelling medical evidence that this could not have been the case, including the existence of “retinal folds”, when the retina rucks up by 360 degrees, at the back of the eye.

The court was told that these injuries were detected immediately after Maeve was admitted to hospital. If the injuries had been caused by a seizure, they would have taken four hours to develop. Such an injury, the court was told, was consistent only with severe trauma, almost inevitably by shaking.

On top of the “triad” of injuries that define “shaken baby syndrome” – swelling of the brain, and retinal and subdural haemorrhaging – the court was told that there had been severing of nerve fibres at the base of the neck and brain, consistent with a whiplash injury.

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