As of 2018, how many Canadians have ever served as Prime Minister of Great Britain?

The only Canadian individual (one man) who has ever served as Prime Minister of Great Britain was Bonar Law. No other person but Law has ever had the honor of being the top executive in the United Kingdom (UK). Law was a British Conservative politician who served as Prime Minister of the UK from 1922 to 1923.

Andrew Bonar Law (Bonar Law as he liked to be called) lived from 1853 until 1923 and has come to be referred to as 'the unknown Prime Minister' by the British press. He was the man who was prime minister for only 211 days; he had the shortest tenure in the job in the Twentieth Century.

Law was born in the British colony of New Brunswick (a colony that became part of Canada). In 1870 he moved to Scotland. He became a successful businessman in the iron industry and was a wealthy man by the age of thirty. In the 1900 general election, Law won the election and entered the House of Commons (the elected lower house of the bicameral parliaments of the United Kingdom). This was the start of his political career.