James Charles Cox (March 3, 1917 - December 20, 2015) was an English Social Democrat politician who served as Prime Minister of England from 1976 to 1977. Before becoming Prime Minister Cox served as Chancellor of the Exchequer from 1969 to 1976, and later served as Foreign Secretary and Deputy Prime Minister from 1982 until his retirement in 1987.
First elected in 1945, spend his first decade in parliament on the backbenches, before becoming shadow Transport minister in 1957. He ran for the party leadership against Arthur Brown in 1964, narrowly losing in a close race. Brown made him shadow Chancellor in a bid for party unity.
When the Social Democrats won the 1969 election Cox was appointed Chancellor of the Exchequer. As Chancellor Cox reformed income tax, increasing the top rate of tax, introduced capital gains and corporation tax and the ill fated wealth tax. He also expanded the welfare state.
Cox suceeded Brown as Prime Minister in February 1976. The SDP had already lost its majority in parliament by the time he became Prime Minister, consequently Cox had to negotiate a confidence and supply agreement with the Liberal Party to remain in office. Rising inflation and high unemployment made the Cox government particularly unpopular, and a wave of strikes in the spring of 1977 caused the Liberal Party to withdraw support for his government. In March 1977 the government was defeated in a motion of no confidence, causing a snap general election.
The election resulted in a landslide defeat for the Social Democrats. Despite this Cox remained leader of the opposition. When the Social Democrats were defeated again at the 1980 election Cox resigned as leader. When the SDP returned to power following the 1982 election he was appointed Foreign Secretary and Deputy Prime Minister, the most recent former Prime Minister to serve in a successors cabinet. He remained an active commentator on political issues until his death in 2015.