By John Sweeney
BBC Real Story
New medical research has cast doubts over the safety of some shaken baby convictions.
A number of similar cases could now be re-opened
One woman whose ex-partner was jailed for murdering her baby daughter tells the BBC how she feels about it.
Five years ago, Lisa Davis's life suddenly fell apart.
She was called to the phone at the care home where she worked as an auxiliary nurse to be told that her 13-month-old daughter Heidi was critically ill.
She rushed immediately to the nearby James Paget Hospital, Great Yarmouth, where the toddler was in intensive care.
There she found her tearful partner, lorry driver Raymond Rock, who said there had been a terrible accident.
Heidi had wriggled out of his arms as he tried to comfort her and landed on the floor.
Heidi had suffered extensive brain damage. She died a few hours later.
Three days later, police officers came to arrest Rock for Heidi's murder.
"I remember the day of his arrest vividly," says Lisa.
"It was Monday morning and there were 10 police officers. They said they had come to arrest him for Heidi's murder and I said: 'No, you've made a mistake'."
A devastated Lisa refused to believe the man she loved and trusted had shaken her baby so violently.
Heidi's injuries were likened to those of an adult who had been hurled into a wall at 70 mph.
One doctor subsequently told Chelmsford Crown Court that Heidi displayed all the classic signs of "Shaken Baby Syndrome" - bleeding and trauma to the brain and eyes.
It was, he said, the worst case he had seen in 30 years of practice.
Only when the jury returned their unanimous guilty verdict did Lisa fully allow herself to believe that Rock had murdered Heidi.
"Gradually, it started to sink in," she says. "The man I loved more than anything had killed my little girl. It was like two losses at once."
Five years on, Lisa is facing the prospect of her world being turned upside down once again.
She may have to accept that 32-year-old Rock is innocent and may be a victim of a miscarriage of justice.
The main prosecution evidence against Rock was the agreement of several eminent experts that Heidi had died of Shaken Baby Syndrome.
But Rock's solicitors are currently preparing an appeal based on new research by a group of British doctors that directly contradicts the central thesis of SBS - that the 'tell-tale signs' of bleeding to a child's eyes and brain is definitive proof of violent shaking.
The dissenting doctors believe babies are far more vulnerable to brain damage than previously thought and that the so-called "tell-tale" signs can be caused by a seemingly innocuous fall of just a few feet - even from a bed or sofa - and cannot be relied on as evidence of abuse.
"It's possible that he is not guilty," says Dr Jennian Geddes, a leading neuropathologist.
"It's entirely possible that people are in prison, convicted of violent shaking, who have in fact done nothing wrong."
Mike Mackey, who represents Sally Clark - who was wrongly convicted of killing her two sons - shares that view.
"I am concerned that the experts on SBS might be wrong too, particularly those cases where there is very little or no other indicators of abuse," he says.
Meanwhile, Rock who is currently in Frankland Prison, Durham, maintains his innocence.
"There is no way he killed that baby," says his father Brian.
"It might be what any father would say of his son, but I know it is the truth."
None of this will ever bring back Heidi.
But last week, when I asked Lisa about the new evidence that points to the fact that Rock might be innocent, her answer was heartrending.
"Well, if that's so, they've ruined my life, haven't they?
"The last five years are going to be a complete and utter lie."
This story is featured on The Baby Killers? Real Story With Fiona Bruce, BBC One 19.30, Monday 29 March