The Sexual Orientation Regulations come into force in Britain today.
It is now illegal to discriminate on the grounds of sexual orientation when providing goods, services and facilities.
Heterosexual people are also covered by the new law, meaning that it is now illegal to refuse them entry into gay bars.
The rules came into force in Northern Ireland on January 1st.
The regulations, which were delayed by Communities Secretary Ruth Kelly, who is the cabinet minister responsible for equality, bring sexual orientation protection into line with similar protections covering religious belief.
The SORs had a controversial passage in Parliament. Labour MPs were furious at suggestions that faith-based adoption agencies were to be exempt.
The Roman Catholic church threatened to close its agencies unless they were allowed to continue to discriminate on the grounds of sexual orientation.
After weeks of debate Tony Blair announced that faith-based adoption agencies have until the end of 2008 to comply with the regulations.
Last month a group of Tory MPs attempted to block the SORs at committee stage, arguing that they had not been given proper time to debate them.
They then forced a House of Commons vote. However, the regulations passed by 310 votes to 100.
29 Tory MPs voted in favour of the regulations, among them party leader David Cameron, gay MPs Nick Herbert and Alan Duncan, Shadow Cabinet members George Osborne, David Willetts, Francis Maude and Theresa Villiers, and Shadow Equality spokesman Eleanor Laing.
The Chancellor of the Exchequer voted in favour of the regulations, as did Ruth Kelly. It was the first time either of them had voted in favour of gay rights.
A motion by Tory peer Baroness O’Cathain seeking to strike down the regulations was defeated in the House of Lords by 168 votes to 122.