John Edward Bernard Seely, 1st Baron Mottistone, CB, CMG, DSO, TD, PC, JP, DL (31 May 1868 – 7 November 1947), also known as Jack Seely, was a British Army general and politician. He was a Conservative Member of Parliament (MP) from 1900 to 1904 and a Liberal MP from 1904 to 1922 and from 1923 to 1924. He was Secretary of State for War for the two years prior to the First World War, before being forced to resign as a result of the Curragh Incident. He led one of the last great cavalry charges in history at the Battle of Moreuil Wood on his war horse Warrior in March 1918. Seely was a great friend of Winston Churchill and the only former cabinet minister to go to the front in 1914 and still be there four years later.
Whilst still on active service in South Africa during the Boer War, Seely was elected Member of Parliament for the Isle of Wight as a Conservative at a by-election in May 1900 and re-elected at the "Khaki" General Election that autumn.
On 10 August 1901, he was promoted to the rank of major in the yeomanry, with the honorary rank of captain in the Army from 10 July. Seely was appointed a deputy lieutenant of the Isle of Wight in 1902.
Along with Winston Churchill and Lord Hugh Cecil he attacked the Balfour government's neglect of the Army. He was a strong believer in free trade and was unhappy with the Unionist (Conservative) Party's increasing support for Tariff Reform (protectionism). He also opposed the Balfour government's support for the use of Chinese Slavery in South Africa. He left the Conservative Party in March 1904 mainly over these two issues and challenged the Conservative Party to oppose him running as an Independent Conservative at the 1904 Isle of Wight by-election. They declined and he was returned unopposed.
He was narrowly elected Liberal MP for Liverpool Abercromby at the 1906 General Election.
Seely was promoted to the rank of lieutenant-colonel in the Hampshire Yeomanry on 20 June 1907, and to colonel on 31 March 1908; he was therefore known as "Colonel Seely" during his time as a politician before the First World War.