John Yates, formerly Britain's most senior counter-terrorism officer, was last night being investigated by the Independent Police Complaints Commission over allegations he gave a job to the daughter of Neil Wallis, the former tabloid figure arrested last week over phone hacking.
As Scotland Yard was plunged into crisis with two high-profile resignations in 24 hours, the IPCC launched an inquiry into "serious allegations" about the conduct of four high-ranking Metropolitan Police officers, including Sir Paul Stephenson - who resigned as Met Commissioner on Sunday - and Mr Yates, who resigned as Assistant Commissioner yesterday. Two other unnamed former senior Scotland Yard officers are also the subject of the investigation, which was triggered by a complaint from the Metropolitan Police Authority, which governs London's police force.
The IPPC said it had been called in to investigate Sir Paul's overall handling of the phone hacking investigation and Mr Yates's review of the investigation in 2009 and "his alleged involvement in inappropriately securing employment for the daughter of a friend."
Its inquiry came last night at the end of another turbulent day for the country's biggest police force, which has been severely criticised for its failure to investigate the News of the World's apparently extensive hacking of the phones of public figures.
On Sunday night, Mr Stephenson resigned hours before a Commons statement on Scotland Yard, saying he could no longer remain in office because of questions about his links to Mr Wallis.
Yesterday, Mr Yates resigned shortly after being told that he was about to be suspended. He insisted in a statement that he had acted with "complete integrity" and his "conscience was clear".