The Metropolitan Police has launched a formal investigation into allegations of sexual misconduct by the Liberal Democrat peer Lord Rennard.
Scotland Yard said that detectives had moved from assessing the claims of a small number of women to carrying out “inquiries to corroborate those allegations”.
The Metropolitan Police set up a dedicated phone line for alleged victims of sexual misconduct after a number of women made claims in the media about inappropriate conduct by Lord Rennard.
The peer, the party's former chief election strategist, has repeatedly denied any improper behaviour or sexual harassment.
He said at the time that he was “disappointed and angry that anonymous accusations from several years ago” were being made public to damage his reputation.
A former Liberal Democrat activist was one of “several women” understood to have called the police hotline.
Alison Smith, now an Oxford University lecturer claimed to have suffered an incident “more serious than having a hand placed on her knee” in 2007.
At the time she said in a statement: “I can confirm that I have just spoken to the confidential police hotline regarding Lord Rennard.”
“The Police are very keen to deal with the matter discreetly, and I agree it is important that other people coming forward should be able to do so without fear of being caught up in the current media storm.
”In addition, it is important that the allegations against Lord Rennard are now dealt with through formal processes.“
In a statement the police said that the investigation had been stepped up from a ”scoping“ inquiry to a full investigation.
”As is standard in cases of an historic nature, officers' initial inquiries are made to establish if allegations of crime are being made and if there are potential victims and witnesses who are prepared to speak to police.
“Officers then carry out inquiries to corroborate those allegations, and in this case that process is ongoing.
”We are not prepared to discuss who, how many or the nature of the allegations made by those who have come forward to police.“
Scotland Yard also refused to say whether Lord Rennard had been interviewed by detectives.
However, it is understood that the potential crimes being investigated are at the less serious end of the spectrum of sex offences. The Liberal Democrat Party is also running two internal inquiries into its handling of the allegations against Lord Rennard.