William Hague is to stand down as foreign secretary with immediate effect and will take on the lesser role of leader of the House of Commons as he prepares to end his political career by retiring as an MP at the next election.
A new foreign secretary will be appointed by the prime minister when he completes his reshuffle on Tuesday. It is understood that it will not be George Osborne, who had been tipped to take the job after the election.
David Cameron praised the outgoing foreign secretary as "one of the leading lights of the Conservative party for a generation" as he announced the dramatic move in the most far-reaching reshuffle since he became prime minister.
Hague's move to become leader of the Commons has echoes of the path taken by Robin Cook after the 2001 election. But that was a clear demotion, unlike Hague who has decided to retire as an MP.
Government sources made clear he could have stayed as foreign secretary had he so wished.
The decision by Hague came shortly after Kenneth Clarke announced that he would be leaving the cabinet as the prime minister embarked on the final planned reshuffle before the general election.
A series of male ministers, including the policing minister Damian Green, the universities minister David Willetts, and the attorney general Dominic Grieve also left the government. Tory sources have made clear that Cameron wants the "old lags" to move on to make way for women and younger men who will be promoted on the second day of the reshuffle on Tuesday.
Esther McVey, the employment minister and former breakfast television presenter, Liz Truss, the childcare minister, Nicky Morgan, the women's minister, Amber Rudd, the whip, Anna Soubry, the defence minister, Priti Patel and Margot James, members of the No 10 policy board, are all expected to be promoted.
The departure of Hague stunned Westminster where it had been assumed that he would remain as foreign secretary until the election, although it had been widely thought he might stand down next year to return to writing history books. Hague had also previously led the Conservatives in opposition from 1997 until 2001, when he resigned after being heavily defeated by Tony Blair at the general election.
Paying a warm tribute to Hague, Cameron said: "William Hague has been one of the leading lights of the Conservative Party for a generation, leading the party and serving in two cabinets. Not only has he been a first class foreign secretary – he has also been a close confidante, a wise counsellor and a great friend. He will remain as first secretary of state and my de facto political deputy in the run up to the election – and it is great to know that he will be a core part of the team working to ensure an outright Conservative victory at the next election."
Hague, who will remain as a member of the national security council, said: "By the time of the general election next year, I will have served 26 years in the House of Commons and it will be 20 years since I first joined the cabinet. In government there is a balance to strike between experience on the one hand and the need for renewal on the other, and I informed the prime minister last summer that I would not be a candidate at the next general election.
"Accordingly I am stepping aside as foreign secretary, in order to focus all my efforts on supporting the government in parliament and gaining a Conservative victory in the general election – after four years in which we have transformed Britain's links with emerging economies, significantly expanded our diplomatic network and the promotion of British exports, restored the Foreign Office as a strong institution, and set a course to a reformed European Union and a referendum on our membership of it."
Hague's departure overshadowed the departure of Clarke, the former chancellor who has championed the European cause as a member of every Tory government since 1972. He resigned from the cabinet with a warning to David Cameron that he will remain in parliament to fight for Britain's membership of the EU.
In a sign that the veteran MP is prepared for a final great battle of his political career in the runup to the prime minister's planned EU referendum in 2017, Clarke said that the case for Britain's membership of the EU is stronger than ever.
Clarke, who secured his first job as a whip in 1972 in Edward Heath's government, was the most high-profile minister to leave office as the prime minister started his long-awaited cabinet reshuffle on Monday afternoon.
The former chancellor made a point of making a high-profile Downing Street visit to the prime minister, who is 26 years his junior, rather than seeing Cameron in the more discreet setting of his House of Commons office. But there were the first signs of a backlash as the scale of the cull of middle aged men became clear when the highly respected policing minister Damian Green was sacked. "It's the night of the long knives and that went really well last time," one Tory said, referring to Harold Macmillan's desperate attempt to shore up his government in 1962 when he sacked a third of his cabinet.
Another senior Tory warned of tokenism as the prime minister prepares to promote large numbers of women today. "This really is the worst form of tokenistic gesture politics," one senior figure said. "Merit is out of the window."David Jones, the Wales secretary, was also among those who left the cabinet , as was David "two brains" Willetts, who resigned as universities minister and is to stand down as an MP at the election next year.
Alan Duncan, the international development minister, also left the government at his own request as did Andrew Robathan, the Northern Ireland minister who was an early Cameron supporter in the 2005 Tory leadership contest.
Nick Hurd, son of the former foreign secretary Lord Hurd of Westwell, is standing down as minister for civil society. Hurd tweeted: "Am standing down having been given by DC the rare opportunity to do six years in a wonderful brief. Very proud of what we achieved."
Stephen Hammond, the transport minister, also resigned.
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