1971-1973 Nullity of Marriage Act and Matrimonial Causes Act
Although the definition of marriage was already defined as between a man and a woman in the Marriage Act of 1949, it was not until 1971 that the Government finally introduced the “Nullity of Marriage Act” explicitly banning same-sex marriages between gay and lesbian couples in England and Wales.
The 1971 Nullity of Marriage Act, because it was the first act to prohibit same-sex unions explicitly, would have made it possible for marriages to be annulled if the partners were not opposite-sex.
Although this Act was in fact repealed, its provisions were again reiterated by the 1973 Matrimonial Causes Act, which is still in force today, and has formed the basis for same-sex marriage legislation.
During this time, Maureen Colquhoun also came out as the first lesbian MP for the Labour Party. When elected she was in a heterosexual marriage. After coming out, her party refused to support her.