So says author John Kerr, who was in Newcastle on Wednesday promoting his new book, The Big Folbigg Mistake - A Mother's Fight For Justice.

"The book makes the case for what can only be described as a fundamental legal error, a problem with the system and great cruelty," Kerr said.

"I usually compare what Kathleen has gone through to Nelson Mandela."

Folbigg, 55, was jailed for 40 years in 2003 after she was found guilty of killing her four babies - Caleb, Patrick, Sarah and Laura - at Singleton and Newcastle in the decade from 1989.

Kerr began following the case when book publisher Penguin asked him to write a book on murder in the family in 2007. He went on to publish the book Bloody Relations, which referred to the Folbigg case.

"I've been writing about crime in Australia for many years. I came across the Folbigg mistake and I thought 'this is as fishy as hell'," he said.

Kerr said there had been a "scientific revolt" against the legal system's conviction of Folbigg. It was widely reported last year that about 90 scientists - including two Australian Nobel laureates - had signed a petition calling for Folbigg's immediate pardon and release from jail.

"Ms Folbigg's convictions were based on the prosecution's theory that she smothered all four children. Yet there is no medical evidence to indicate smothering," the petition stated.

The petition came after scientists discovered Folbigg's two daughters had a previously unknown genetic mutation, which could lead to sudden and unexpected infant death. Her two sons also had rare mutations, which could have led to early death.

Kerr said petitions to free Folbigg had now been signed by about 300 scientists.

"I think it's the biggest single scientific revolt since the nuclear disarmament campaign in the '50s. I can't find another one as big as this."

He said the first petition was signed by "both our Nobel laureates in physiology and medicine [professors Elizabeth Blackburn and Peter Doherty]".

"Since then Brian Schmidt, the astrophysicist and bloke who said the universe is expanding and not slowing down like we thought, has signed the petition."

A jury convicted Folbigg, but Kerr thinks the jurors were misled.

"There's a huge respect in the legal profession for a jury verdict. I have no quarrel with the jurors, but it's no use saying you can confine everything in a juror's mind to court," Kerr said.

American paediatric forensic pathologist Dr Janice Ophoven was reported as saying at Folbigg's committal hearing that the chances of four unexplained infant deaths from natural causes was "one in a trillion".

This statistic was later discredited and discarded from Folbigg's trial.

"But by then The Sydney Morning Herald had blasted it all over the front page. It's kind of memorable, one in a trillion, isn't it," Kerr said.

"I think the jury were deluded by a whole lot of nonsense surrounding the case. The prosecuting counsel said lightning doesn't strike in the same place twice. That was using numbers that were already discredited."

Folbigg's diary entries were presented by the prosecution as incriminating evidence that she had deliberately killed her children by smothering them.

Kerr said a small amount of words were cherry-picked from the 50,000 words contained in the diaries.

People that read the entire diaries would "never get four homicides out of that in a thousand years". The diary entries were "pretty lightweight compared with genes that don't work".

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