Angela Cannings, who has continued to protest her innocence since being jailed for life for murdering her two infant sons, today launched a bid to clear her name in the court of appeal.

Cannings, 40, from Salisbury, Wiltshire, has always claimed that her children died of cot death and asked the panel of three judges to rule her conviction unsafe.

Her counsel, Michael Mansfield QC, told the court that the jury that convicted his client must have come to the extraordinary conclusion that she was "giving birth in order to kill".

To suggest that Cannings went on having babies over a period of 10 years, knowing she might be overcome by an urge to kill the child she was giving birth to like a character in a Greek tragedy, "beggars belief", he said.

Mr Mansfield argued that the jury had reached an unsafe verdict in the face of a mass of expert evidence to the effect that the deaths could have been due to sudden infant death syndrome, or cot death.

There was no evidence that she was mentally unstable, and witnesses including family, work colleagues, neighbours, her local priest, doctors and health visitors had described her as a supportive, loving, caring mother.

Cannings, 40, a shop assistant, was found guilty by a jury of eight women and four men at Winchester crown court in April last year of the murders of seven-week-old Jason in 1991 and 18-week-old Matthew in 1999.

During her six-week trial, the court heard that she had been alone with both boys, who were asleep in their cots, when they died. They had appeared well in the hours before their deaths, but on each occasion she had found them gasping for breath, floppy and blue.

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

Her appeal follows 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.

One of the witnesses who gave evidence against Cannings was Professor Sir Roy Meadow, whose research was also a key factor in the Clarke and Patel cases. His claim in the case against Mrs Clarke, that the chance of two children of the same family dying of cot death was "73 million to one", has been challenged by recent research suggesting that, because of genetic links to cot death, the odds could be as short as 64 to one.

Cannings, who is serving her sentence in Bulwood prison in Essex, was brought to the court of appeal in London so that she could listen from the dock to the arguments in her appeal. Her husband Terry and members of her family were also in court.

The case continues, with the hearing expected to last five days.