Arthur Greenwood CH, PC (8 February 1880 – 9 June 1954) was a British politician. A prominent member of the Labour Party from the 1920s until the late 1940s, Greenwood rose to prominence within the party as secretary of its research department from 1920 and served as Parliamentary Secretary to the Ministry of Health in the short-lived Labour government of 1924. In 1940, he was instrumental in resolving that Britain would continue fighting Nazi Germany in World War II. He was also noted for problems with alcoholism.Greenwood was first elected to the House of Commons at the 1922 general election for the constituency of Nelson and Colne in Lancashire. He held the seat until being defeated at the 1931 election, but returned to Parliament the following year, winning a by-election in the Yorkshire constituency of Wakefield. Greenwood continued to represent Wakefield until his death in 1954.Greenwood became deputy leader of the Labour Party under Clement Attlee. Arguably his most famous moment came on 2 September 1939 when, acting for an absent Attlee, he was called to respond to Neville Chamberlain's ambivalent speech on whether Britain would aid Poland. Preparing to respond, he was interrupted by an angry Conservative backbencher, Leo Amery, who exclaimed "Speak for England, Arthur!"A flustered Greenwood proceeded to denounce Chamberlain's remarks, to the applause of his colleagues. When the wartime coalition government was formed, Winston Churchill appointed him to the War Cabinet as Minister without Portfolio in 1940. He was generally seen as ineffectual, but in May 1940 he emerged as Churchill's strongest and most vocal supporter in the lengthy War Cabinet debates on whether to accept or reject a peace offer from Germany. Without the vote in favour of fighting on by Greenwood and Clement Attlee, Churchill would not have had the slim majority he needed to do so.After that his position declined and he resigned in 1943. The same year, he was elected as Treasurer of the Labour Party, beating Herbert Morrison in a close contest.Until the end of World War II, Greenwood also performed the function of Leader of the Opposition, though he did not receive the salary.During the Attlee government, he served successively as Lord Privy Seal and Paymaster-General.Greenwood's son Anthony Greenwood (later Lord Greenwood) (1911–1982) was an MP from 1946 until 1970, first for Heywood and Radcliffe and later for Rossendale, and a member of Harold Wilson's governments.