Britain and Canada protested yesterday over a proposed law that would result in gays in Uganda being imprisoned for life or even executed.

Gordon Brown followed Stephen Harper, the Canadian Prime Minister, in telling Uganda that the legislation was unacceptable.

Mr Brown made his views plain in a breakfast conversation with President Museveni of Uganda on the margins of the Commonwealth summit.

Homosexuality remains criminalised in many Commonwealth countries, but the more liberal countries have been horrified by the new legislation.

The Anti-Homosexuality Bill 2009 is going through Uganda’s Parliament after receiving its first reading last month.

According to Clause 2 of the Bill, a person who is convicted of gay sex is liable to life imprisonment. But if that person is also HIV positive the penalty — under the heading “aggravated homosexuality” — is death.

The Bill has not been endorsed by the Ugandan government but it has allowed it to proceed, and some top officials are said to have praised it.

A Canadian government spokesman said: “If adopted, a Bill further criminalising homosexuality would constitute a significant step backwards for the protection of human rights in Uganda.”

The Bill proposes a three-year prison sentence for anyone who is aware of evidence of homosexuality and fails to report it to the police within 24 hours. And it would impose a sentence of up to seven years for anyone who defends the rights of gays and lesbians.

Addressing the Commonwealth People’s Forum, Stephen Lewis, the former UN envoy on Aids in Africa, said that the Bill made a mockery of Commonwealth principles. “Nothing is as stark, punitive and redolent of hate as the Bill in Uganda.”