TRAGIC mother Angela Cannings walked to freedom yesterday - innocent of murdering her two baby sons and determined to be "mummy" to her surviving daughter.

Her release by three appeal court judges from a life sentence came amid continuing doubt about the causes of cot death, which she has always insisted killed her boys.

A tearful Mrs Cannings held hands with her husband, Terry, on the steps of the Royal Courts of Justice, in London, as she recalled that her first child - a girl - had also died of sudden infant death syndrome.

The four years since the death of her last baby had been a living hell, she said.

She said: "Finally today, justice has been done and my innocence has been proven."

Their surviving seven-year-old daughter had been her inspiration to carry on, she said.

"I would like now to go home with Terry and, for me especially, to be mummy to our very precious daughter."

The Court of Appeal overturned a jury's verdict in April last year that Mrs Cannings smothered seven-week-old Jason, in 1991, and 18-week-old Matthew, in 1999.

She was not charged over the death of her first child, Gemma, at the age of 13 weeks, in 1989.

Her surviving daughter, who cannot be named for legal reasons, was born in January 1996.

At the end of a five-day hearing, Lord Justice Judge said the court had reached the clear conclusion that the convictions were unsafe and should be quashed.

The judge, sitting with Mrs Justice Rafferty and Mr Justice Pitchers, said the case raised issues of public interest in relation to cot death and they would take time to reflect on how to express the reasons for their judgement.

The appeal centred on an argument that the Winchester Crown Court jury was faced with the "impossible task" of weighing up conflicting expert evidence given by eminent paediatricians on each side, who disagreed over the cause of death.

The case followed a decision earlier this year to overturn solicitor Sally Clarke's conviction of murdering her two young sons, and the acquittal of pharmacist Trupti Patel on charges of murdering her three babies.

Lawyers for Mrs Cannings claimed that one prosecution expert, paediatrician Professor Sir Roy Meadow, had given misleading evidence that three cot deaths in one family was "very, very rare", leading to the conclusion the cause of death was smothering.

Research by Professor Meadow was also a key factor in the Clarke and Patel cases.

Mrs Cannings' solicitor, Bill Bache, said after her release: "Still nobody knows what causes cot death and, until a good deal more information is known about that, it would seem to me that prosecutions of the kind that have been brought against her should not continue."

The ruling once again draws attention to the way cot death is investigated.

Gillian Latter, North-East regional co-ordinator for the Foundation for the Study of Infant Deaths, said: "We have been campaigning for the last two years for sudden infant death syndrome to be investigated very thoroughly and in a uniform way across the UK.

"Every baby who dies suddenly and unexpectedly deserves the proper investigation to find out, if we can, what has caused that baby's death, especially as it may have implications for other babies in the family."

She said the foundation's research had shown that where a baby had died suddenly and unexpectedly, there was a slight risk of it happening again in the family. In many cases, the cause of death is never determined.

Mrs Latter said: "Parents feel guilty when their baby dies because they feel it is something they should have prevented - but you can't always."

The risk can be reduced by parents following the foundation's advice, which includes placing the baby to sleep on its back, stopping smoking and making sure the baby is not too hot.

* The foundation can be contacted on 0870 7870554.