Below is a timeline of events that led to the resignation of Assistant Commissioner Bob Quick.
Wednesday, April 8th
8.30am:Chief Constables arrive in Downing Street for meetings with Prime Minister Gordon Brown and Home Secretary Jacqui Smith about community policing.
Photographers Steve Back from Political Pictures and Dan Kitwood from Getty capture their arrival along with a Sky News camera crew.
9.30am:As the meeting is breaking up and the chief constables are leaving No10, a silver Land Rover pulls up carrying Mr Quick. He is photographed getting out of the vehicle holding a sheaf of papers.
10.30am:Getty transmits a version of the photograph showing a partially obscured close-up of the documents Mr Quick is carrying.
12.00pm:Mr Back transmits his version of the photograph which, when enlarged, clearly shows Mr Quick holding a document marked SECRET: Operation Pathway. It details plans for seizing terror suspects in an "executive action" following an MI5-led terror investigation.
2.40pm:The Press Association publishes a D-Notice issued by the Government's Defence Press and Broadcasting Advisory Committee which advises media outlets that publication of the image would "seriously damage national security".
5.00-6.00pm:Hundreds of police raid 10 properties across the North West of England and arrest 12 men - including 10 Pakistani nationals on student visas and one Briton.
7.30pm:Shadow home secretary Chris Grayling says Mr Quick's blunder is an "extraordinary and very alarming lapse" which raises "serious questions" about his judgment.
8.00pm:Speaking to the BBC, Home Secretary Jacqui Smith congratulates police on the anti-terror operation but will not be drawn on questions over Mr Quick's future. During the evening, she meets with Mr Quick and then with his boss, Met Commissioner Sir Paul Stephenson.
Thursday, April 9th
8.20am:London Mayor and Met Police chairman Boris Johnson announces Mr Quick's resignation as head of counter-terrorism on the Today programme on Radio 4. He said it followed "consultations" overnight but denied there was a "witch hunt" to get him out.
9.05am:In a statement Mr Quick said he "deeply regretted" having potentially compromised a major anti-terror operation. Assistant Commissioner John Yates is confirmed to take over as head of specialist operations.