How Whitehall leaks turned into crisis for the Yard

November 2007 to September 2008
Galley begins leaking documents to the Tories in November 2007, possibly earlier. The Conservatives acknowledge that four leaks took place; the Home Office claims 20 incidents are under investigation. Leaks include revelations that: licences had been granted to security guards who were illegal immigrants and Home Secretary Jacqui Smith kept it secret; an illegal immigrant was working as a cleaner in the Commons in February this year; and a draft letter from Ms Smith to Downing Street in August warned that a recession could lead to a rise in crime

October 2008Sir David Normington, permanent secretary at the Home Office and nicknamed the "smiling assassin", begins an internal inquiry into the leaks. In the second week of October, the Cabinet Office calls in the Met Police. The request goes to Assistant Commissioner Bob Quick, head of specialist operations and a former chief constable of Surrey. Quick's role puts him in charge of Counter Terrorism Command. Quick tells Sir Ian Blair, then Met Commissioner, that he intends to launch a full investigation. A week earlier Sir Ian had resigned after pressure from Mayor Boris Johnson. Sir Paul Stephenson, his deputy and now acting commissioner, is told of the inquiry.

19 November
Galley, who earns £25,000 as an assistant private secretary, is arrested at his home in Feltham in Middlesex on suspicion of misconduct in a public office. He is taken to a central London police station and held for several hours. During questioning, his lawyer says, he volunteered the whereabouts of his computer, mobile phone and other documents. He is released on bail. Police also remove property from a business address in central London.

21 November
Galley is re-arrested and bailed again.

27 NovemberGreen, 52, is arrested at 2pm and held for nine hours "on suspicion of conspiring to commit misconduct in a public office and aiding and abetting, counselling or procuring misconduct in a public office". Police search his home and offices in Kent and his office in Parliament. They seize computers and documents including letters to his wife and confidential details of constituents. He is bailed.

Jacqui Smith insists she was not aware of the arrest before it took place, possibly because she was in Brussels. Gordon Brown insists he was only informed afterwards.

Commons Speaker Michael Martin is told of the planned arrest at least seven hours beforehand. Martin insists he was merely informed of the decision and that permission for police to enter the Commons was given by Jill Pay, the Serjeant at Arms. Stephenson telephones Boris Johnson, who is also chair of the Metropolitan Police Authority, at 10am to tell him an MP is to be arrested. Forty minutes before the arrest he telephones again to tell the Mayor it is Green. The Director of Public Prosecutions Keir Starmer is informed of the decision.

30 November
Amid a growing furore, the Tories reveal Green was accused during questioning by police of "grooming" Galley, a phrase with paedophile connotations. The claim suggests police believe Green encouraged Galley to leak papers. MPs threaten to disrupt tomorrow's state opening of Parliament.

1 December
Galley holds a press conference. His solicitor Neil O'May says Green was Galley's only contact in the Commons and that the leaked documents were important to holding the Government to account. Closing date for applications for Met Commissioner: both Quick and Stephenson apply.

2 December
Scotland Yard calls in the Chief Constable of the British Transport Police to oversee a review of police tactics.