He first entered Parliament in the 1964 election, and resigned from Edward Heath's government in protest at the British signup to the EEC. He was close to Margaret Thatcher, but lost his Glasgow Cathcart seat at the 1979 election. He re-entered at a 1980 by-election, for Rochford and Southend East following the death of Steven McAdam.
Policies of his include withdrawal from the European Union, the re-introduction of capital punishment, and beating in schools. During John Major's government he was one of the Maastricht Rebels, and was expelled from the party.