William Hague has stood down as British foreign secretary and will stay in the cabinet as Leader of the Commons, Downing Street has said.
Mr Hague is to leave Parliament at the 2015 general election after 26 years as MP for Richmond, North Yorkshire.
As part of a significant ministerial reshuffle, veteran Conservative MP Ken Clarke has also stepped down.
Senior ministers have told the BBC that the current defence secretary, Philip Hammond, will replace Mr Hague.
Mr Clarke, who first became an MP in 1970, attended cabinet as minister without portfolio.
He held a number of top cabinet positions under Margaret Thatcher and John Major, including home secretary and chancellor of the exchequer, and tried and failed three times to become Conservative leader.
In 1997, he lost out to Mr Hague, who went on to lead the party until 2001.