Bono's surprise appearance at Tory conference

He went on: "It's a brave thing: keeping Britain's aid promise to the developing world, but it is the right thing to do and it is what's great about Great Britain."

Tory sources were careful afterwards to say that the message was not intended as an active political endorsement from Bono, who appeared last week in a video message to introduce Gordon Brown's keynote speech at Labour's gathering in Brighton.

But the speech gave the impression that the celebrity activist may be preparing to work with another political party, after his long and close association with Labour.

His message was introduced by William Hague, the Shadow Foreign Secretary, who described Bono as someone "you don't normally hear from at Conservative conferences".

Bono has acknowledged in the past that he is seen as "Labour's apologist" over his defence of the government's attempts to drive deals on international poverty and the Aids crisis.

In 2004 he appeared on stage at the Labour Party conference, praising Tony Blair and Gordon Brown for their achievements and calling them the John Lennon and Paul McCartney of the global development scene.

In 2005 Mr Blair invited him and fellow anti-poverty campaigner Bob Geldof to speak at the G8 summit when it was hosted by Britain at the Gleneagles Hotel.

The singer still retains close links with the Labour hierarchy. Three weeks ago he ran into Mr Blair in Chicago, as he was playing a concert and the former prime minister was on business in his advisory role for Zurich Financial Services.

" Bono is here doing the U2 concert so we hooked up last night. We had a nice conversation about various things we're doing in Africa," Mr Blair revealed afterwards.

And on September 22 Bono was photographed clasping Mr Brown warmly at a ceremony in New York when the Prime Minister was presented with the World Statesman of the Year award by the Appeal of Conscience Foundation.

The Irish multi-millionaire has spent a decade lobbying western governments on behalf of the world's poor, urging action on the woes of the poor from debt relief to Africa's HIV/Aids epidemic.

Since 2005 he has become an annual fixture at the G8 summit of the world's most powerful leaders, and often appears at the World Economic Forum in Davos. His efforts have earned him three Nobel Peace Prize nominations, in 2003, 2005 and 2006, and an honorary knighthood.

He has also been criticised for feeding his own ego with his campaigns. Paul Theroux dismissed him in 2005 as one of a group of celebrity "mythomaniacs, people who wish to convince the world of their worth", and accused him of perpetuating the lie that Africa was fatally troubled and could only be saved by outside help.

Bono responded to his critics in The Times on February 19, 2006, calling them "cranks carping from the sidelines".

"A lot of them wouldn't know what to do if they were on the field. They're the party who will always be in opposition so they'll never have to take responsibility for decisions because they know they'll never be able to implement them," he riposted.

Copyright 2009 Times Newspapers Ltd.