In a wide ranging question and answer session, Mr Brown told Labour's conference that resolutions condemning the situation had been passed by the world's developed nations, but they had not been followed up.

"I don't want to look back a few years from now and say we should have acted, we could have acted but we didn't act."

Mr Brown said the UN resolutions had to be backed up by a force on the ground.

"It's got to be the biggest force that's ever been put into Africa. Then we've got to start the political talks. Then we've got to get a ceasefire on the ground."

If the aerial bombings by the military did not stop, further sanctions should be applied.

"The message we've got to send out is that we are prepared to back up the struggle of Africans for basic rights and economic and social freedom - whether it is in Darfur or Zimbabwe - we are prepared to play our part.

"But we want to work with the Africans who are fighting for democracy."