Leading article: Stakes are high for the new Commissioner

Despite Sir Paul Stephenson's optimistic demeanour outside Scotland Yard yesterday, there can be no disguising that the new Commissioner of the Metropolitan Police is taking over a deeply unstable and unhappy ship.

In recent months the Met has been convulsed by accusations of racist management from senior officers and a public row with the London Mayor that led to the departure of the previous Commissioner, Sir Ian Blair. The force is also reeling from the damning findings of the inquest into the shooting of Jean Charles De Menezes. Sir Paul will have all that strife to contend with from the moment he sits down at his new desk. And at the same time he will need to get to grips with delivering law and order in one of the world's great cities, not to mention the various national policing responsibilities of the Met.

The new Commissioner at least has an object lesson from his predecessor in how not to go about tackling the job. Sir Ian's mistake as Commissioner was his attempt to play politics. Such a high profile job is, of course, inescapably political to some extent; even more so now that the Commissioner has both a Labour Home Secretary and a Conservative Mayor to answer to. But the head of the Met should not add to those political pressures, as Sir Ian did by, among other things, briefing MPs in support of the Government's anti-terror legislation.

As acting commissioner in the wake of Sir Ian's departure, Sir Paul got a taste of the political pitfalls that come with the job when his officers raided the House of Commons offices of the Conservative immigration spokesman Damian Green. The raid was a heavy-handed breach of parliamentary privilege. But to his credit, Sir Paul did not seek to duck responsibility for sanctioning it. Providing the new Commissioner has learnt from this mistake, there is some comfort to be drawn from the leadership he demonstrated over the matter.

The political challenges are significant, but the policing agenda is no less crowded. Two major areas of concern are terrorism and nihilistic youth violence. And an early headache for the Commissioner promises to be discontent over the rising number of stop and searches. Stop and search has its place. But there is strong evidence that overuse is having a detrimental effect on community relations. In an ethnically-diverse city like London it is essential that all groups have confidence in the police.

The Met has improved significantly since the 1999 Macpherson report labelled the force as "institutionally racist". The number of ethnic minority officers has increased and attitudes have generally improved. Sir Paul must make sure that the force does not go backwards under his command.

There are new challenges too. During Sir Ian's tenure, overall crime fell in London, largely thanks to benign economic conditions. Sir Paul will not be so fortunate. Acquisitive crime is projected to rise as the grip of recession grows tighter. He needs a strategy to deal with this. Policing the 2012 Olympics is another major challenge.

The present turmoil within the Met and the intense outside scrutiny it has attracted of late ensures that the stakes are perilously high. If Sir Paul succeeds in steadying the ship and improving his force's performance he will go down as a significant Commissioner in the force's long history. If he fails, the calls for this sprawling police empire to be broken up into its constituent parts might well prove irresistible.