Helen Cummings celebrates her friend Kathleen Folbigg's release from prison

The campaign began after a 2011 book by an Australian academic lawyer, Murder, Medicine and Motherhood, concluded Folbigg was wrongly convicted.

Ms Cummings began the crusade with a letter to then NSW Attorney General Greg Smith in 2013, after a year of corresponding with and visiting Ms Folbigg.

Ms Cummings was expecting a call from Ms Folbigg as she spoke to ACM's Newcastle Herald today about coming to terms with the news of her release from prison.

"We were sorting out a new petition, and now we don't have to," Ms Cummings said from her Newcastle home.

"She's only just been released now, she is being picked up by her best friend.

"I am still coming to terms with it. It's been too long, 20 years for something she didn't do but, I've been visiting her and corresponding with her and phoning her ... for the last ten years.

READ MORE: Kathleen Folbigg to walk from jail after pardon

"There have been many disappointments along the way. The first inquest was a very big disappointment, when (then Chief Judge of the District Court, Reginald Blanch AM QC) said he wasn't interested in the content of her diaries, which just broke our hearts."

The second inquiry was a different kettle of fish, Ms Cummings said, when Sophie Callan SC, assisting the inquiry, said the conclusion had been reached that there was substantial evidence pointing to reasonable doubt about Ms Folbigg's guilt.

"So when she said those words, I thought this is the beginning, it's going to still take time, but for her to say that, and then the DPP, who had been fighting to keep her there, agreed, we knew, yes.

"Thanks to the scientists and the new evidence, all of this new evidence that proved beyond doubt that the two girls had died of natural causes and the two boys, there was a gene ... to show epilepsy was the cause of the death of one of the boys."

Ms Folbigg was charged over the deaths of all four children, so as soon as one of those had fallen over on the evidence, the other three should have fallen, but nonetheless the battle was over, Ms Cummings said.

"It's just the best news," she said. "I can't wipe the smile off my face. I had tears in my eyes when I found out but now I can't stop smiling.

"It's a big day here for Kathleen, justice at last has been served and it's taken too long but it's happened, and my thoughts are with my friend.

"I hope she is sitting up to a T-bone steak right now and a bath."

The matter would now need to proceed to the Criminal Court of Appeal for the conviction to be quashed, Ms Cummings said.

"The governor Margaret Beazley doesn't have that power, and the Attorney General doesn't have that power. That power sits with the Criminal Court of Appeal and I will be hoping beyond hope they will quash it."

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