Sir Paul Stephenson, the Met's Deputy Commissioner, is taking over following the resignation of Sir Ian Blair.

The 55-year-old, a former Chief Constable of Lancashire, is one of the front runners in the race for the permanent job of Commissioner, which is expected to be finalised by the spring.

One of his most pressing tasks will be to deal with the fallout from the arrest of Conservative MP Damian Green, which has outraged many MPs.

Sir Paul has already faced tough questions over the shadow immigration minister's arrest.

He steps into the role after Sir Ian failed to win the backing of London Mayor Boris Johnson, leading to the police chief's resignation.

Born in Bacup in 1953, Sir Paul rose through the ranks of the police, working in Northern Ireland, Merseyside and Lancashire. He became a police superintendent at the age of 34 and moved to Ulster in the early 1990s before returning to Lancashire in 1994 as a sub-divisional commander in Preston. He was Chief Constable of Lancashire Constabulary from July 2002 to February 2005.

In July 2006, he received an Honorary Fellowship from the University of Central Lancashire in Preston and he was knighted in this year's Birthday Honours.

He has been serving as Deputy Commissioner of the Metropolitan Police Service, and is seen by many commentators as likely to land the Commissioner's job permanently. However, he faces competition from Northern Ireland Police chief Sir Hugh Orde, Merseyside head Bernard Hogan-Howe, West Midlands boss Sir Paul Scott-Lee and Cambridgeshire Chief Constable Julie Spence.