Police are investigating whether "criminal activity" took place following allegations of inappropriate behaviour towards women by senior Liberal Democrat peer Lord Rennard.
Scotland Yard disclosed that it had been approached by party officials in the wake of claims Lord Rennard had exploited his former position as chief executive to proposition women and to touch them inappropriately.
"The Metropolitan Police Special Investigations Command has been approached by officials in the Liberal Democrat Party and is working with them to ascertain whether or not criminal activity has taken place," a spokesman said.
The party said on Monday night that it would "engage fully" with the police on the issue.
"We can confirm that the party has had an invitation to attend a 'stakeholder meeting' at Scotland Yard to discuss the involvement of the police in any investigation into Chris Rennard," a Lib Dem spokesman said. "The party will fully engage with the police on this issue and continue to encourage anyone with allegations of a criminal nature to contact the police."
Lord Rennard, who was the Lib Dems' key election strategist and adviser to a succession of party leaders, has strongly denied the allegations made against him by a series of Lib Dem women.
Party leader Nick Clegg has come under sustained pressure to explain what exactly he had known about the claims and what he had done about them.
The Lib Dems initially insisted Mr Clegg had known nothing about them until a Channel 4 News report broke the story on Thursday. On Sunday, however, the Deputy Prime Minister returned from holiday in Spain to concede that his office had heard "indirect and non-specific concerns" as far back as 2008. He said that his then chief of staff Danny Alexander had put the concerns to Lord Rennard who denied any inappropriate behaviour. The following year the peer stepped down as chief executive citing ill health.
Mr Clegg's position was not helped when Lib Dem president Tim Farron, referring to the way the case had been handled, said the party had "screwed this up". Speaking to BBC Radio Solent days ahead of Thursday's crunch Eastleigh by-election, Mr Clegg said: "I have got nothing to hide, the party has nothing to hide. We have now got to listen to the women who feel they weren't properly listened to and get to the truth and that is what we will do."
Speaking outside his home in south-west London, Mr Clegg told Sky News: "I understand there are many people who appear to want to act as self-appointed detectives trying to piece together events that happened many years ago but the only way that we are going to get to the bottom of the truth, the only way we are going to ensure that the women whose allegations were broadcast on television last week are properly listened to, the only way we are going to establish exactly what happened and who knew what and when, is by allowing the two investigations that I established immediately after the Channel 4 broadcast to do their job and, indeed, to allow the police, whom we have now approached, to do their job as well. And in the meantime I cannot and my party cannot provide a running commentary on every shred of speculation about events which happened many years ago."