Mayor Boris says he's chairman of the board. They'd better be good

Boris Johnson has, amazingly, won. The Conservative Party has recaptured the capital city. It last held the former Greater London Council in 1981 - just before Ken Livingstone became its leader. This is a momentous day for Londoners and for Britain as a whole.

Tonight, massive media attention will focus on Boris, now the leader of Europe's biggest city. Labour will be in despair, particularly with the party's worst-ever performance in the local elections beyond the capital. It is a dreadful portent for Labour: if they cannot hold London with Livingstone as their candidate, what chance will they have in a general election? A dozen or more marginal Labour Parliamentary seats in the capital now appear vulnerable to David Cameron's advance.

Over the weekend, Mayor Johnson will have to announce details of his City Hall team. Wykehamist policy guru Nicholas Boles has been working to produce names for months.

We should also expect hints about early policy changes. The new Mayor's team will want to show it is both competent and different from the previous incumbent. It will need to avoid accusations of a rapid move of mayoral style from Stalin (Livingstone) to Mr Bean (Johnson) and establish Boris as the "chairman" of an organisation with competent executives. The Tories nationally will not want to find themselves under pressure because of their London Mayor's failures.

Sorting out City Hall will not be easy. Mayoral systems of government are operated by a team of trusted individuals selected by the office-holder. As Livingstone's clique fills the removal vans, Johnson's appointees will start to move in. A key figure in the changeover will be Anthony Mayer, chief executive of the permanent staff and a "transition team" already in place. He and his civil service-type colleagues will steady the ship as people get on and off. Indeed, Team Boris may come to rely more heavily on the full-time officials than Ken's advisers did.

Tonight we say farewell to Kenneth Robert Livingstone, leader of the GLC from 1981 to 1986 and Mayor of London from 2000 to 2008. No politician since Herbert Morrison, who led the London County Council from 1934 to 1940, has dominated London like Ken.

He was still, in the recent campaign, able to galvanise a huge and complex "rainbow coalition" of minorities into voting for him. But on this occasion the inner-city coalition was not sufficient to stop the march of the suburbs.

It is impossible to know this evening whether London politics has seen the last of Livingstone. He could, like Tony Blair, choose to become a rich man. Many company boards, television programmes and conferences would pay handsomely for his services.

Other Labour would-be mayoral candidates will start to emerge ahead of 2012. Tessa Jowell, Trevor Phillips and Nick Raynsford may fancy their chances.

But tonight is Boris's. A funny, engaging and largely untested figure now represents London. More seriously, he will have direct responsibility for the city's transport, planning and economic development. Indirectly, he can influence policing and the emergency services. It is in his best interests - and ours - that he governs well.

Tony Travers is director of the Greater London Group at the London School of Economics