Sydney Arnold, 1st Baron Arnold (13 January 1878 – 3 August 1945) was a radical British Liberal Party politician who later joined the Labour Party and served as a government minister.
A son of W.
A.
Arnold, of Manchester, he was educated at Manchester Grammar School.
As a member of the General Committee of the Manchester Liberal Federation, he served as Honorary Treasurer of the North-West Division of the Free Trade Union.He unsuccessfully contested the Conservative seat of Holderness Division of the East Riding of Yorkshire at the December 1910 General Election.
He was elected in 1912 as Member of Parliament for Holmfirth in what was then the West Riding of Yorkshire at a by-election following the resignation of the long-serving Liberal MP Henry Wilson.
In 1914 he was appointed Parliamentary Private Secretary to Jack Pease, the President of the Board of Education.
He was also appointed Parliamentary Private Secretary to Edwin Samuel Montagu the Financial Secretary to the Treasury.
During the war he served as a captain in the South Staffordshire Regiment.When his constituency was abolished for the 1918 general election, he was elected for the new Penistone constituency against a Coalition Government endorsed Unionist candidate.
He supported a levy on capital and the nationalisation of the mines and railways.