Prime Minister Gordon Brown supported the defeat of a California gay marriage ban. Brown called California's Proposition 8 “unacceptable.”

The Downing Street reception was organised to celebrate LGBT History Month attended by prominent gay leaders. This was the first time the LGBT community had been invited to a reception at number 10.

The Labour Party legalized civil partnerships for gay and lesbian couples in 2005. They have also overseen open gay service in the military since 2000.

Proposition 8 reversed a California Supreme Court ruling allowing gay marriage in the state when it defined marriage as a heterosexual union in the state constitution. Voters approved the measure by a narrow 52%. Yesterday, the state Supreme Court heard arguments in a lawsuit that seeks to void the measure. A decision is expected in 90 days.

Discussing Proposition 8, Brown said “This attempt to undo good that has been done is unacceptable. This shows why we have always got to be vigilant, always got to fight homophobic behavior and any form of discrimination,”

He also praised UK gay rights leaders for “changing opinion” about civil unions for gays and lesbians, “You've shown how the legislative process, by your pressure, can respond,” Brown said.