Sir Paul Stephenson has been appointed as the head of the Metropolitan Police Service.

Sir Paul, 55, who has served as deputy to former commissioner Sir Ian Blair for four years, was chosen ahead of Sir Hugh Orde, the Chief Constable for Northern Ireland.

Jacqui Smith, the Home Secretary, and London Mayor Boris Johnson agreed on his appointment after interviewing the final two candidates on Monday.

Sir Paul has been leading the force as acting commissioner since his boss stepped down in October after losing the Mayor’s support.

Shortly after he took on the post, he was plunged into controversy over the arrest of the Conservative frontbencher Damian Green by Met officers investigating Home Office leaks.

During his tenure as Met deputy, Sir Paul also faced questions over the police shooting of the innocent Brazilian Jean Charles de Menezes in the wake of the London bombings.

But today he said he was “an immensely proud policeman, to be entrusted with leadership of the Met and delivering security for the many millions who live in and visit London”.

His first task will be to restore confidence in the Met after a difficult year in which it was faced with accusations of racism.

Sir Paul said his agenda was “about cutting and solving crime, securing our streets, convincing all our communities that we are on their side and delivering the policing they want, and being intolerant of violence in any form”.

He added: "Our job is to be visible on the streets, never walking by when help is needed and having pride in our uniform, our badge and the world famous Scotland Yard brand.

"In short, we must deliver. It’s my job to lead this.”

Sir Paul will be paid £253,000 a year to lead more than 50,000 staff and oversee a budget of £3.5 billion.

As Britain’s most senior policeman, he will be expected to lead the national police strategy against terrorism and run the security at the London 2012 Olympics.

The Mayor said he was “thrilled” with Sir Paul’s appointment. “I believe he was the clear choice in a strong field of candidates for the position of Commissioner.”

Mr Johnson added that he was “impressed” with Sir Paul’s conduct as acting commissioner and believe he would “rebuild Londoners' confidence and pride” in their police force.

Sir Paul started his career with Lancashire Constabulary in 1975 and then moved on to Ulster Constabulary.

He has served as assistant chief constable of Merseyside and chief constable of Lancashire before moving to the Met in 2005 as Sir Ian’s deputy.

His rival, Sir Hugh, spent most of his 32-year career in the Met, rising to deputy assistant commissioner before leaving in 2002 to head up the Police Service of Northern Ireland (PSNI).

Two other applicants, West Midlands police chief Sir Paul Scott-Lee and Merseyside head Bernard Hogan-Howe, have been eliminated in earlier rounds.