Bonar Law was born in New Brunswick in Canada in 1870 to Ulster Scots parents. He was educated at the High School of Glasgow and began work at the family bank, Kidston’s, when he turned 16. After that, he worked in the iron industry, establishing himself as a successful businessman.

In 1900, Bonar Law was elected to the House of Commons as MP for Glasgow Blackfriars. He was an enthusiastic supporter of Joseph Chamberlain’s proposed tariff reforms, though this did not stop him from participating in Balfour’s government as a Parliamentary Secretary. But tariff reform split the Conservative Party, and in the 1906 election, Bonar Law lost his seat.

He returned to the Commons later that year, now representing Dulwich. It was at this time that he developed a friendship with media publisher Maxwell Aitken, the future Lord Beaverbrook, whose supported Law’s career.

Bonar Law made a mistake during the 1910 election, abandoning his Dulwich seat for North-West Manchester, which he failed to win. He only returned to the House in March 1911 when he won the by-election for the Bootle constituency.

Balfour resigned from the Conservative leadership later that year, and spurred on by Aitken, Bonar Law announced that he would run too. Few thought he would win, but his rivals, Austen Chamberlain and Walter Long, were so committed to preventing each other from becoming leader, they both ended up endorsing Bonar Law. Thus was Bonar Law elected unanimously by Conservatives at the Carlton Club in November 1911.

Bonar Law threw himself into the Home Rule crisis. Dublin rule for Ulster was, in his words, ‘the imposition of tyranny’. He offered his support to the armed leaders of the Orange Order and the Ulster Volunteer Force. He even tried to persuade the King to exercise the royal veto. Ultimately, the outbreak of the First World War in August 1914 prevented (or at least, postponed) conflict in Ireland.

During the First World War, Bonar Law became a keen supporter of the government. He joined the Liberals in a coalition government in March 1915. There, he earned a reputation as being contemplative, but, eventually, decisive. Over 1915-16, he became more frustrated with Prime Minister H. H. Asquith’s running of the war. When the crisis came, he declined the premiership in favour of Lloyd George. Bonar Law became Chancellor in Lloyd George’s cabinet.

Lloyd George and Bonar Law were very different men, but they worked well together. Bonar Law even agreed to continue the wartime coalition when the war ended in 1918, with Bonar Law continuing as Lord Keeper of the Privy Seal and Leader of the House of Commons. With his health deteriorating, Bonar Law resigned in 1921.

Then, in October 1922, Conservative MPs chose to end the coalition, against the wishes of their party leadership in October 1922. Requiring new leadership, Bonar Law took over both the Conservative leadership and the premiership. In the 1922 election, he campaigned on a manifesto of ‘tranquillity and stability’, winning a majority of 75. He resigned in May 1923 due to illness and died in October 1923.

His wife Annie, with whom he had six children, died in 1909 following an operation, and two of his sons were killed in the First World War, both in 1917.