Anglican and Catholic Church leaders joined forces yesterday in a battle to be excused from new British anti-discrimination laws they say would force Catholic adoption agencies to place children with gay couples. The leader of the world’s 77 million Anglicans, Archbishop of Canterbury Rowan Williams, backed Britain’s leading Catholic cardinal in urging the government to exempt Catholic adoption agencies from the new law, which comes into force in April. In a joint letter with the Archbishop of York John Sentamu, Williams told Prime Minister Tony Blair: “The rights of conscience cannot be made subject to legislation, however well-meaning.” The letter piles pressure on Blair, who commentators say is leaning towards the church’s view, but who would face a fierce backlash from within his party if he allowed an exemption.