John Jagger (1 October 1872 – 9 July 1942)^[1] was a British trade unionist and Labour Party politician. After a career in business and trade union leadership, he won a seat in the House of Commons in 1935, and held it until his death in a road accident.

Jagger spent the early part of his career in business, and travelled for four years as a business manager in India, China and Burma.^[2] He then became a departmental manager in co-operative stores.^[2]

He was chairman of the York Trades and Labour Council,^[3] and became president of the Amalgamated Union of Co-operative Employees, of which he was the chief founder. In 1921 he became general president of the National Union of Distributive and Allied Workers,^[3] and held that post until he entered Parliament in 1935.

At the 1935 general election, he was elected as the Member of Parliament (MP) for Manchester Clayton,^[4] defeating the Conservative MP William Flanagan.^[5] The seat had been won by Flanagan in 1931 after it had been held by Labour since 1922.^[5]

In December 1935 he was a speaker at the Congress of Peace and Friendship with Russia, held in Friends House on the Euston Road in London.^[6] In July 1936, he was one eleven MPs who sent a telegram to Prime Minister of Spain expressing their "admiration of the heroic fight being put up by the Spanish people against the attack of Fascists".^[7] The MPs pledged themselves "to do everything in our power to rally behind your struggle the whole British people".^[7]

In 1938, he was one of the Labour MPs who visited Spain during the Civil War.^[2] In May 1940, when Herbert Morrison became Minister of Supply in the wartime coalition government, Jagger was appointed as his Parliamentary Private Secretary (PPS).^[2] Morrison was promoted to Home Secretary in October 1940, and Jagger remained his PPS in the new post.^[2]

In July 1942, the 69-year-old Jagger had been staying in a cottage in Beaconsfield in Buckinghamshire.^[2] On 9 July he was riding his motorcycle to Beaconsfield railway station when he collided with a car, and was killed instantly.^[2] His death caused a by-election in Manchester Clayton, when the seat was held for Labour by Harry Thorneycroft.^[8]

Jagger married Martha Southern in 1899, and they had two sons.