The senior peer Lord Lester of Herne Hill is facing a suspension from the House of Lords after he was found to have sexually harassed a woman during his parliamentary career.
The Lords Privileges and Conduct Committee recommended he should be suspended until June 2022 after offering the complainant “corrupt inducements” to sleep with him.
Lord Lester also “warned her of unspecified consequences” if she did not accept his offer.
Peers are expect to vote on Thursday whether to accept the committee's recommended punishment, which would be the longest suspension in modern parliamentary history.
Lord Lester responded to the allegations on social media, calling the claims "completely untrue".
"These allegations are completely untrue. I produced evidence which clearly demonstrated that what I was said to have done 12 years ago did not happen," he said.
"Independent counsel who previously advised the Committee on its procedures provided an advice which concluded that the investigation was flawed and unfair. I regret the Committee’s conclusions in the light of these materials.
"There has to be a fair process for investigating sexual harassment claims in Parliament.
"Parliament is supposed to be a bastion of the rule of law but calls for fundamental reform of this procedure have been ignored for 20 years. I hope to be judged by my work over decades for gender equality, race relations and free speech."
It follows an investigation by the Lords Commissioner for Standards Lucy Scott-Moncrieff after the woman - who has not been identified - complained the peer had breached the Lord's Code of Conduct.
In its report the committee said: "We endorse the conclusion of the commissioner that in respect of that conduct Lord Lester of Herne Hill breached provisions of the code in failing to act on his personal honour by sexually harassing the complainant and offering her corrupt inducements to sleep with him."
Prominent QC Lord Lester, 82, announced in February he was stepping down as a Liberal Democrat spokesman on human rights and withdrawing from the party whip following the complaint.
A subsequent report by the sub-committee on Lords' conduct found his actions constituted a "grave abuse of power" and recommended he should be expelled altogether.
'A tragic irony'
However, the main Privileges and Conduct Committee accepted that, at the time the behaviour which led to the finding took place, there was no power of expulsion and recommended it should be substituted with a term of suspension.
Report from the Sub-Committee on Lords’ Conduct said that Lord Lester’s actions were a “tragic irony” that the peer had previous known for campaigning for “racial and sexual equality”.
It added that Lord Lester had become “obsessively attracted to the complainant” and that it was “quite out-of-character” for the peer.
In recommending a suspension to June 3, 2022 - past the due date of the next general election - the main committee said it had taken into account the length of previous suspensions as well as the seriousness of the case.
"Lord Lester made a dishonourable promise backed by a dishonourable threat," it said.