Shadow minister Jack Dromey has insisted he did not give his approval to a call for the age of sexual consent to be reduced to as low as 10 that was issued by a civil liberties organisation he chaired in the 1970s.
The Sun reported that a meeting of the executive committee of the National Council of Civil Liberties (NCCL), attended by Mr Dromey in 1976, agreed that the body should propose lowering the minimum age for sex to 14, or 10 in certain circumstances.
Former Labour Cabinet minister Patricia Hewitt apologised last night for the links between the NCCL and a paedophile rights campaign group and said that, as general secretary at the time, she took responsibility for mistakes that were made.
According to The Sun, Ms Hewitt's name was on an NCCL press release in March 1976 which called for a reduction in the age of consent and the legalisation of incest.
But in a statement, Mr Dromey said he did not give his agreement to the proposal at the committee meeting a month earlier, and was "a resolute opponent" of the Paedophile Information Exchange (PIE) when he became chairman a few weeks later.
"I did not agree with the proposal in February 1976 to lower the age of consent," said Mr Dromey, now a home affairs spokesman in Ed Miliband's Labour frontbench team.
"When elected chairman of NCCL weeks later, I made it clear that my first priority would be to take on the child sex abusers of PIE. I then defeated them by a massive majority at the annual conference in April.
"My stand was denounced in a leaflet distributed by PIE to the delegates to the conference. I closed the conference saying that we had to protect children from sexual abuse and that adults guilty of sexual abuse were the lowest of the low. I was throughout a resolute opponent of a vile organisation."
In her first public comments since the current controversy broke in the Daily Mail, Ms Hewitt said the NCCL had been "naive and wrong" about the PIE in the 1970s.
The former MP, who served as health secretary in Tony Blair's government, said: "I got it wrong on PIE and I apologise for having done so."
Ms Hewitt - who said she was able only now to respond to the reports, having been away for the past 12 days - said any suggestion that she had condoned or supported the "vile crimes" of child abusers was "completely untrue".
According to The Sun, Ms Hewitt's was the only name on the press release publicising the NCCL's call for a reduction in the age of consent.
The document, the newspaper claims, said: "NCCL proposes that the age of consent should be lowered to 14, with special provision for situations where the partners are close in age, or where consent of a child over 10 can be proved."
Referring to an NCCL report on reforming sex laws, it says: "The report argues that the crime of incest should be abolished. It says 'In our view, no benefit accrues to anyone by making incest a crime when committed between mutually consenting persons over the age of consent'."
The Sun also reported minutes of an NCCL executive committee meeting in London in January 1976 which proposed reforms saying that a person under the age of 10 in a sexual relationship is incapable of giving consent.
But, the minutes said, if a sexual partner is over 10 and under 14, while there is a "rebuttable presumption" that no consent was given, a defendant "should have to prove that the child consented and understood the nature of the act to which consent was given".
Ms Hewitt, a former health secretary, acknowledged that it had been NCCL policy to cut the age of consent - although she said the proposal to do so had not been hers.
"I do not support reducing the age of consent or legalising incest," Ms Hewitt said. "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."
Ms Hewitt's willingness to apologise for past errors is in sharp contrast to Labour deputy leader Harriet Harman, who has insisted she has nothing to apologise for over her involvement with the NCCL at the time.
Ms Harman has accused the Mail of mounting a campaign of "smear and innuendo" after it used documents unearthed in the NCCL's archives to highlight its links with PIE at a time when she, her husband Mr Dromey, and Ms Hewitt were all prominent in the organisation.
In her statement, Ms Hewitt, who was general secretary from 1974 to 1983, said she should have done more to protect the integrity of the NCCL from the activities of PIE, which was allowed to join the organisation as an affiliate member.
"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'," she said.
"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."
In particular, she said that PIE secretary Tom O'Carroll should never have been allowed to join the NCCL's gay rights sub-committee.
Ms Hewitt also defended the roles played by Ms Harman and Mr Dromey.
"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," she said.
"Harriet 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."
While Ms Hewitt said there were still lessons to be learned about the need to protect children from sexual abuse, she said she was proud of the achievements of the NCCL during her time as general secretary.
"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," she said.
"I hope the lessons that are being learnt from the mistakes of the 1970s will contribute to those goals."
Prime Minister David Cameron believes Ms Hewitt's apology was "the right approach", Number 10 said as Ms Harman remained under pressure to follow her example.
Tory defence minister Anna Soubry told BBC1's Question Time that the Labour deputy leader had handled the story "very badly".
"If she had just come out and apologised, it would have gone away," she said.
"I don't think she has done herself any favours. Neither has Jack Dromey."
Asked if Mr Cameron agreed, a Downing Street spokeswoman said: "It's a matter for Harriet Harman but the PM thinks that what Liberty, Shami Chakrabarti and Patricia Hewitt have done is the right approach.
"I don't think the PM is going to give Harriet Harman PR advice and expertise. It's a matter for her."
Ms Chakrabarti, the present director of Liberty - the name later adopted by the NCCL - has described the involvement of PIE as " a source of continuing disgust and horror".
In a statement released in December, Ms Chakrabarti said: " It is a source of continuing disgust and horror that even the NCCL had to expel paedophiles from its ranks in 1983 after infiltration at some point in the Seventies.
"The most important lesson learned by Liberty over the subsequent 30 years was to become a well-governed modern human rights movement in which protecting the vulnerable, especially children, will always come first."