A senior Conservative MP has said that the use of the term 'counter terrorism police' can be misleading.
Sir Malcolm Rifkind (Con, Kensington and Chelsea), a former foreign secretary, questioned why officers from the Metropolitan police's counter-terrorism also investigate non-terrorism offences.
Today Met assistant commissioner Cressida Dick gave evidence to a Commons committee investigating police searches on the parliamentary estate.
Damian Green, shadow immigration minister, was detained by counter terrorism police on November 2008.
His Commons office was searched as part of an investigation into a leak from the Home Office.
Police did not obtain a warrant for the search, which angered many MPs.
Green was not charged with any offences.
Rifkind said that the use of the term 'counter terrorism' had left the then-Speaker of the Commons, Michael Martin, with the impression that an MP was being investigated on terrorist activity.
In fact they were investigating Green on suspicion of misconduct in a public office.
He said Met police officers "misled" the Speaker and the Serjeant at Arms about the nature of the investigation.
Dick said it was "very important" that officers make clear who they are, where they are from and what they are investigating and it was "very regrettable" if anyone was confused.
Rifkind replied that House officials were misled and not confused.
He said "any reasonable person" would expect there to be terrorism involved and asked if it is "wise" for an organisation to call itself counter terrorism when it investigates other matters.
The police failed to inform the Serjeant, responsible for Commons security, that they were not investigating terrorism offences, he added.
In 2006 the Met's counter terrorism command was created, taking over the roles and responsibilities of the anti-terrorist branch and special branch, to "bring together intelligence analysis and development with investigations and operational support activity".
Dick said that officers in the command have the skills to deal with an investigation that may involve national security.
She promised to "go away and think" about its name and admitted there may be a need for officers to "clarify" what they are investigating.
Sir Menzies Campbell (Lib Dem, North East Fife), chair of the committee, said that Speaker Martin had given evidence that he felt he could not interfere with a counter terrorism investigation.
Rifkind said that the Met should change either the counter terrorism command's name or the command structure.
Dick also defended the police's decision to investigate Green for misconduct in public office.
She said the law is used "quite regularly" in the police, prison service and in government departments.
In the Met police district in the past 18 months there have been 58 arrests and 31 people have been charged, making it "useful and important" rather than an obscure law, she told the committee.
Dick added that Green was investigated for aiding, abetting or procuring the leak of information from the Home Office.
The committee has now concluded its public hearings and is expected to publish its report in March.
