Scotland Yard has tripled the number of officers investigating historic allegations of sex abuse in the wake of claims of a Westminster cover-up over a paedophile ring - and the probe now extends into East Anglia.

Metropolitan Police Commissioner Sir Bernard Hogan-Howe said today that the number of officers looking in to decades-old allegations has been beefed up to “well over 20”.

Speaking to the Police and Crime Committee at London’s City Hall he said of the sex abuse claims: “We’ve tripled the number of people in there this week. Well over 20 people will be dedicated to that and we will make an assessment of the cases.

“It takes a little while because sometimes victims will have moved on to other parts of the country, sometimes abroad, and that poses its own challenges. Not all the people are prepared to tell us all the details or to go on to the criminal justice process.”

To date the force had refused to discuss what action it was taking in the wake of the fresh concerns raised over a dossier handed to former home secretary Lord Brittan in the 1980s.

Scotland Yard already has its own inquiry, Operation Fairbank, which was launched in response to information passed on by MP Tom Watson, who used Prime Minister’s Questions in 2012 to air claims that there was a paedophile ring with links to Number 10.

He claimed that a file of evidence used to convict a man called Peter Righton of importing child pornography in 1992 contained “clear intelligence” of a sex abuse gang, and claimed that a member of the group had bragged about links with a senior aide to a former Prime Minister.

Sir Bernard said that similar inquiries are already being staged in a number of areas across the UK.

He told the committee: “If you look at the allegations of historical sexual abuse involving allegations against MPs there are at least six inquiries: Northern Ireland, north west, north Wales, East Anglia, Leicestershire and London.

“At the moment we are assessing what these developments will mean and we are trying to get to the bottom of how many of these allegations are allegations where there is a suspect and how we will deal with it.”