One option Boris was considering was an inquiry into the Met's links with the News of the World and former executives of the paper like Neil Wallis by another police force, HMIC - the inspector of constabulary - or the IPCC - the Independent Police Complaints Commission.

BBC: An old-fashioned resignation?

Metropolitan Police Detective Inspector Michael Hawkins told the court he was handed an envelope containing torn pieces of paper in October 1990.

BBC: Asil Nadir employee 'tore up transfer evidence'