Scotland Yard heaped fresh pressure on one of Britain’s most senior law enforcement officials when a senior Met detective directly contradicted evidence given to Parliament by the head of the Serious Organised Crime Agency (Soca).

Trevor Pearce, the agency’s director-general, has come under fire after telling MPs last week that his investigators immediately passed key computers containing evidence of hacking by blue-chip companies, high-profile individuals and law firms to the Metropolitan Police.

However Commander Neil Basu, who is leading the Met’s multiple inquiries into phone hacking and the bribing of public officials by newspapers, said that his officers did not have all the evidence seized by Soca during another inquiry in 2009.

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When the Home Affairs Select Committee asked if the Met “had the hard drives”, Commander Basu said: “We wouldn’t necessarily possess all the information from that previous investigation.”

This jars with what Mr Pearce told the Committee last week, when he said: “As soon as we became aware that there may have been information on (the computer)... all of that information – the hard drive, supporting documentary evidence, statements, and indeed follow-up inquiries from our officers – was provided to the Metropolitan Police.” Mr Pearce has been reported to the Independent Police Complaints Commission by the hacking victim Ian Hurst, who claims the Soca chief committed “contempt of Parliament”.

Keith Vaz MP, chairman of the Home Affairs Select Committee, said: “There is a gap between what the head of Soca told us last week and what Scotland Yard has told us today. This is serious and the Committee will be writing urgently to both organisations to seek clarification.”

Investigators from Soca seized hard drives from an investigator working for the News of the World during a raid in 2009. Despite evidence of criminality, he was not investigated for serious offences until the phone-hacking scandal erupted in 2011.

It is understood the investigator has privately admitted working on behalf of an array of clients, including celebrities, high-profile businessmen and private companies such as law firms.

Following revelations two weeks ago in The Independent, the Home Affairs Select Committee asked Soca to provide a list of the clients who had commissioned the private investigator who “are not newspaper people”.

Parliament questioned several senior Met officers were asked about other damaging revelations, including claims undercover police officers sought “dirt” to discredit the family of Stephen Lawrence. Sir Bernard Hogan-Howe, the Metropolitan Police Commissioner, said the allegations were shocking.