Cherie to be bid envoy

Cherie Blair is to be officially appointed as a roving ambassador to lobby for London's bid to stage the 2012 Olympic Games.

The Prime Minister's wife will be one of a handful of envoys who will work throughout the two-year campaign to bring the Games to Britain for the first time in more than 60 years. She will join a small team, which will include double Olympic gold medallist Sebastian Coe, charged with "selling" London's bid around the world.

Other leading figures - almost certainly including David Beckham - will be brought into the campaign team closer to the July 2005 date when the host city for 2012 will be chosen.

The news of Mrs Blair's role, which is bound to be greeted with controversy in some quarters, comes ahead of the expected appointment of American Barbara Cassani as chairman of the London bid. Ms Cassani, former chief executive of the no-frills airline Go, is expected to be confirmed in the role tomorrow.

But it is Mrs Blair's appointment which is likely to cause the most stir. She will be expected to lobby hard on London's behalf when she accompanies Tony Blair to summits abroad. This could start next month when the Prime Minister leaves for China, Japan and South Korea, a visit originally scheduled for the spring which had to be postponed because of the war with Iraq. The role will mean Mrs Blair liaising closely with the Foreign Office, and with British embassies overseas.

She will also have to make sure she does not breach tough International Olympic Committee guidelines on lobbying. IOC chiefs are said to take a dim view of countries-which try to take an unfair political advantage. Mrs Blair, not known for her keenness on sport at school, is nevertheless said to be a keen fan of athletics. She attended last year's Commonwealth Games in Manchester and this year's world championships in Birmingham. A well-placed source said: "She wants to be involved in any way she can."

London faces tough competition from Paris, Madrid and New York among other competing cities. The final vote will be held in Singapore, with Mrs Blair certain to attend. She could be joined there by her husband in a last-minute diplomatic push for support, if London looks close to being awarded the prize.