Former Labour Health Secretary Patricia Hewitt has apologised for having "got it wrong" in the 1970s in the row over a pro-paedophile group.
Hewitt, who served as general secretary of the National Council for Civil Liberties in the 1970s, said she now accepts responsibility for the mistakes that were made in relation to the Paedophile Information Exchange (PIE).
The two organisations were affiliated for eight years from 1975 to 1983. Hewitt said she believed PIE was a "campaigning/counselling group for adults" whose objectives had been "misunderstood" by the wider public.
She now accepts that she was "naive and wrong" to accept PIE's claims.
In a statement she said: "NCCL in the 1970s, along with many others, was naive and wrong to accept PIE's claim to be a 'campaigning and counselling organisation' that 'does not promote unlawful acts'.
"As general secretary then, I take responsibility for the mistakes we made. I got it wrong on PIE and I apologise for having done so.
"I should have urged the executive committee to take stronger measures to protect NCCL's integrity from the activities of PIE members and sympathisers and I deeply regret not having done so."
However, she insisted that she had never condoned the "vile crimes" of paedophiles.
Among the policies of the PIE was decriminalising sex with children as young as four. At least seven members of the organisation were jailed for paedophilia offences.
Hewitt acknowledged that it was the NCCL's policy to lower the age of consent, but denied she was behind the idea.
"I do not support reducing the age of consent or legalising incest. As the NCCL archives demonstrate, I consistently distinguished between consenting relationships between homosexual men, on the one hand, and the abuse of children on the other."
Labour deputy leader Harriet Harman was also caught up in the row when it came to light that she served as the legal officer of the NCCL, now known as Liberty, while her husband, Labour home affairs spokesman Jack Dromey, was on the executive.
Harman has said that she regretted the links between the two groups, but stated that she is the victim of a "politically motivated smear campaign" and that allegations made against her were "horrible and untrue".
Hewitt went on to defend Dromey and Harman over their roles within the organisation in the 1970s.
"When Jack Dromey, as NCCL chairman in 1976, vigorously opposed PIE at the NCCL AGM, he did so with the full support of the executive committee and myself as general secretary.
"Harriet [Harman] did not join the NCCL staff until 1978. She was one of two legal officers, neither of whom was a member of the executive committee."
Hewitt continued, saying that lessons must be learnt and greater emphasis must be placed on protecting children from abuse.
"Although the evil of child sexual abuse is now properly recognised, as a society we still have a long way to go in protecting children, tackling the sexualisation of girls and supporting the survivors of sexual abuse. I hope the lessons that are being learnt from the mistakes of the 1970s will contribute to those goals."
It is the first time Hewitt has publicly spoken since the controversy broke twelve days ago. The 65-year-old claimed she was away.
Meanwhile, it has emerged that Hewitt shared a conference platform with PIE leader Tom O'Carroll in 1977.
Speaking to the Radio 4 Today Programme, O'Carroll claimed the two women 'didn't even try' to remove the paedophile group from the NCCL, fearing it would harm their careers.
"At the time Harman and Hewitt couldn't just kick us out, or they could but they didn't try. The reason was their careers in the NCCL depended upon them not rocking the boat too much."