The BBC's Vicki Young reports: "He's a highly decorated and experienced officer"

John Stevens, 56, has taken on a couple of the toughest jobs in policing - heading enquiries in Northern Ireland and into corruption inside the Met.

He needed a thick skin for those challenges and he will need it just as much to take the Met into the new millennium.

The force has been battered with criticism following the murder of Stephen Lawrence, the black teenager stabbed to death by racists in South London in 1993.

Mr Stevens will have to raise the morale of his 26,500 officers and at the same time change the Met's racist, sexist and homophobic image.

His career has taken a conventional path for high-flying policemen.

His first job was in the Met. He then soared up the ranks with various forces, including Hampshire, Cambridgeshire and Northumbria.

He also made the smart career move of a spell in the Inspectorate of Constabulary where officers pick up on Home Office politics.

The Met badly needs a new image

What marks him out from his contemporaries are the two "missions impossible" he was asked to carry out.

He led an inquiry into the 1989 murder of Pat Finucane, a Catholic lawyer in Northern Ireland.

He ignored the advice of the former Deputy Chief Constable of Greater Manchester, John Stalker, who headed a long running inquiry into "shoot to kill" allegations in the province.

After all his problems with the complex affairs of Northern Ireland, Mr Stalker suggested that anyone asked to perform a similar duty should "go sick."

Since May of last year, Mr Stevens has led the Met's inquiry into claims of corruption within its own ranks.

That is another of policing's most thankless tasks but so far John Stevens has escaped unscathed.

Met's new masters

Mr Stevens was one of five candidated interviewed for the £130,000-a-year job.For the first time the post was advertised.

As well as rebuilding the Met's relations with London's ethnic minorities, the new commissioner will have to deal with different masters.

The elected Mayor of London and the new assembly will have a big say over policing in the capital.