After losing a second successive election in October 1974, Heath insisted he would continue as leader, but in January 1975, Margaret Thatcher announced she would challenge Heath for the leadership, and on 4 February, she narrowly outpolled him in the first round. Heath chose to resign the leadership rather than contest the second round. Heath returned to the backbench, where he would remain until 2001. In 1975, he played a major role in the referendum on British membership of the EC, campaigning for the eventually successful "Yes" vote to remain in the Community. He would later become an embittered critic of Thatcher during her time as prime minister, speaking and writing against the policies of Thatcherism. Following the 1992 election, he became Father of the House, until his retirement in 2001. He died in 2005, aged 89. He is one of four British prime ministers never to have married. He has been described by the BBC as "the first working-class meritocrat" to become Conservative leader in "the party's modern history" and "a One Nation Tory in the Disraeli tradition who rejected the laissez-faire capitalism that Thatcher would enthusiastically endorse."