Harriet Harman has said she has nothing to apologise for over the involvement of a civil rights organisation she used to work for with a paedophile rights campaign.
The Labour Party deputy leader said she had never "colluded" with the Paedophile Information Exchange (PIE) while she was legal officer of the National Council for Civil Liberties (NCCL) in the 1970s.
And she called for an apology from the Daily Mail - which has highlighted links between PIE and the NCCL - for running what she described as a campaign of "smear and innuendo" against her.
The paper's consultant editor Andrew Pierce hit back, saying Ms Harman and her husband Jack Dromey - who was also prominent in the NCCL - should have done more to disassociate the civil rights body from PIE.
Ms Harman began the day by issuing a statement through a spokeswoman expressing her "regret" that the NCCL - now known as Liberty - had ever become involved with PIE.
It followed a bruising interview last night on BBC2's Newsnight in which she repeatedly refused to say that it had been a "mistake" for the NCCL to have allowed PIE to become an affiliate member in the 1970s.
By today, she had returned to the airwaves to resume the offensive, insisting her work at the NCCL had not been in any way affected by the link with PIE.
"I'm not going to apologise because I've got nothing to apologise for," she said in pooled television interview with ITV News
"I very much regret that this vile organisation, PIE, ever existed and that it ever had anything to do with NCCL, but it did not affect my work at NCCL.
"They had been pushed to the margins before I actually went to NCCL and to allege that I was involved in collusion with paedophilia or apologising for paedophilia is quite wrong and is a smear.
"It is actually not me that should be apologising for something that I haven't done. It is the Daily Mail that should be apologising for their smear and innuendo."
She also attacked the newspaper on Twitter for publishing photographs of young girls in bikinis, writing "When it comes to decency and sexualisation of children, would you take lessons from the Daily Mail?".
Mr Pierce said that it was wrong to try to conflate images of girls that could be seen on "any British beach" with the "grotesque" activities of PIE.
He said that Ms Harman and Mr Dromey - who is now a shadow home office minister - still needed to explain why they had not done more to end the links between the two organisations.
"Their offence was not to publicly disassociate from this organisation," he told BBC Radio 4's The World At One.
"It matters enormously that they did not do more to get rid of this horrible, disgusting organisation."
He said Ms Harman had been one of the politicians making the "loudest noise" about the Jimmy Savile scandal, demanding transparency from the organisations involved.
"She has not applied that same high quality of standard to her own work at the National Council for Civil Liberties," he said.