Labour’s deputy leader Tom Watson has said he had met Carl Beech – convicted of lying about VIP abuse – to offer him reassurance on behalf of the police.
Mr Watson has been accused of encouraging Beech, who had made claims about people from politics, the military and the intelligence agencies.
Beech claimed they were part of a paedophile ring in the 70s and 80s.
Police say they cannot find any record of contact between the force and Mr Watson on this subject.
On Monday, Beech was convicted of inventing claims of abuse and murder. He will be sentenced at Newcastle Crown Court on Friday.
Former MP Harvey Proctor, who was one of the men named by Beech, has since accused Mr Watson of giving “oxygen” to Beech’s false claims against him.
Information from Mr Watson had generated several investigations after he claimed in Parliament in October 2012 that secret files relating to a different case could show there was “powerful paedophile network linked to Parliament and No 10”.
In November 2014 detectives launched the disastrous Operation Midland, which spent 18 months looking into his claims of abuse and murder, conducting raids of suspects’ homes and interviews under caution along the way.
Speaking to the BBC, Mr Watson said Beech had come to his office in Parliament on 8 July 2014, which was three months before the start of several lengthy interviews with the Metropolitan Police.
The Labour MP said the “purpose of the meeting was to reassure him that the Metropolitan Police had assured me that they would take him seriously if he made allegations.”
He added: “My job was to convince him that the police would listen to his story. The police asked me to reassure him that they’d take him seriously.”
A spokeswoman for Mr Watson later added that, before the meeting with Beech, he spoke to a police officer who asked him to provide the assurances, but that Mr Watson could not remember who this was.
A spokesperson for Scotland Yard said it had not identified any records at this time relating to such contact.
Mr Watson said he was introduced to Beech by a journalist from the now defunct website Exaro News and a retired child protection manager.
Mr Watson said Beech never told him the names of the public figures he was accusing.
But in January 2015 – following the death of Lord Brittan, also one of the men Beech accused – he wrote an article for the Sunday People about the late peer, stating: “I have spoken to those who claimed he abused them. So these allegations have come to me first-hand, not through insinuation or innuendo”.
In a reference to Beech, he said he’d “spoken to a man” who had made serious abuse allegations against Lord Brittan.
The article accompanied the revelation that Lord Brittan was under investigation by Operation Midland.
When it was pointed out this was inconsistent with his claim never to have spoken to Beech about the accused, a spokeswoman for Mr Watson said he had never talked to Beech about Lord Brittan, but had received an email about him from the accuser.
The newspaper article quoted Beech, although he was not identified at the time, saying that Lord Brittan was “as close to evil as a human being could get”.
Mr Watson said he had previously apologised to the family of Lord Brittan for this.
Apologising again, he said: “I strongly regret writing that. All I can say is, I felt quite emotional, at the time, that a criminal enquiry had not been completed and I thought people might be feeling that justice had not been done.
“I’m genuinely sorry for the hurt that caused Lady Brittan in particular”, he said.
He expressed further “regret” when shown a tweet from February 2015 in which he had stated: “I think I have made my position on Leon Brittan perfectly clear. I believe the people who say he raped them.”
Lord Brittan died during the police investigation, without being informed that they had concluded there was no case against him.
Mr Watson said, following the meeting with Beech, “there was some limited email exchanges, mainly me showing sort of courtesy and support.”
His office has been asked to provide the dates of these contacts, but has not yet done so.
During his police interviews with the Met Police, Beech said Watson had been part of a “little group that was supporting me and trying to put some of my information out there to try and encourage others to come forward”.
Daniel Janner QC, whose father Lord Janner was one of those falsely accused by Beech, said: “Tom Watson is guilty of politicising the police. He used the police for his own political ambitions and gain. He should resign.”
He added that asking Mr Watson to provide reassurances to Beech was “also wrong from a policing point of view.”