Brown joins Harper against Uganda's Anti-homosexuality Bill 2009

A Downing Street source said: "The Foreign Office will be following the passage of the bill closely and we will continue to do everything we can privately and publically to prevent its passage . . . it has been raised in the strongest terms at the highest possible level today."

The bill, which had its first reading in Parliament last month,would mean death or life imprisonment for those convicted of homosexuality. Those found guilty of "promoting" homosexuality would also received harsh punishments.

The death penalty would be used against those found guilty of "aggravated homosexuality"- a sexual act where one person has HIV or AIDS.

Gay rights groups have urged Commonwealth leaders to throw Uganda out of the Commonwealth unless it drops the proposed law.

Earlier this month, the Foreign Office told PinkNews.co.uk: "The adoption of the bill could do serious damage to efforts to tackle HIV and its criminalisation of organisations that support homosexuality could, in theory, encompass most donor agencies and international NGOs.

"The UK, alongside our EU partners, has raised our concerns about the draft bill and LGBT rights more broadly with the government of Uganda, including with the prime minister and several other ministers, the Ugandan Human Rights Commission, and senior officials from the Ugandan Ministry of Foreign Affairs.

"We will continue to track the passage of the bill and to lobby against its introduction."

Although Brown's discussions with President Museveni have not been made public, his spokesperson said that he raised the issues and that the British government's view on this matter was clear.

Brown's position was echoed by Canada's prime minister Stephen Harper. His spokesman said: "If adopted, a bill further criminalising homosexuality would constitute a significant step backwards for the protection of human rights in Uganda."