A woman at the centre of allegations that a Liberal Democrat peer sexually harassed party activists is expected to make a formal complaint to police today.

Alison Smith, a Lib Dem activist who is now a lecturer at Oxford University, said she planned to talk to officers about claims that Lord Rennard behaved inappropriately towards her.

She claims an alleged incident in 2007 was "more serious" than having a hand placed on her knee.

"I will be talking to the police and I think the trial by media, probably it is time for that to finish," she told BBC News.

Ms Smith said she decided to "blow the whistle" about the peer's alleged behaviour because he had started to become involved again in training events.

"We were told he was not going to make a comeback, now here he is, turning up all over the place," she added.

Nick Clegg's handling of the affair has been repeatedly called into question. An initial response from the party suggested that he was not aware of the allegations but the party leader later admitted he had known of general concerns.

He conceded yesterday that his party made "very serious mistakes" in failing to deal properly with complaints made about the peer.

Pressed on whether the issue played any part in Lord Rennard's departure as chief executive in 2009, the Deputy Prime Minister told LBC 97.3: "Like any new leader of any organisation or political party, I wanted to make sure that the organisation reflected my priorities, my values.

"I felt it was time for a change at the top of the professional party. His health was poor and that was the immediate reason he left but of course these things were in the background."

Lord Rennard, who stepped down as chief executive on health grounds, has said he is ready to "co-operate with any properly-constituted inquiry" into allegations of inappropriate behaviour.

The peer has issued a series of strenuous denials of any wrongdoing.

Scotland Yard has met senior Liberal Democrats to investigate whether any criminal activity has taken place and the party has launched two internal inquiries.

Meanwhile, Mr Clegg, visiting the Aston Martin car factory in Warwickshire today, told reporters that he wanted the investigations into Lord Rennard's alleged behaviour carried out "as quickly as possible".

"The key thing, not least for the women involved, is that the investigations get their work done as quickly as possible," he said.

"The important thing is that the two investigations I announced last week are allowed to get on with their work, and that the police investigation is allowed to get on with its work.

"It's crucial we get to the bottom of the truth and do that as soon as possible.

"That's why the investigations should proceed as quickly as possible."