London ( CNN ) -- William Hague announced his resignation as Britain 's foreign secretary , in what was perhaps the biggest surprise of a major government reshuffle by Prime Minister David Cameron . Hague , who has served in the role for four years , will be the leader of the House of Commons until next year 's general election . Hague said he was proud of the work he had done in the Foreign Office but that he 'd been involved in politics for a long time . He was first elected to Parliament in 1989 and , among other roles , led the Conservative Party in opposition from 1997 to 2001 . `` Renewal in politics is good , and holding office is not an end in itself . After 26 years as an MP , time will be right for me to move on , '' he tweeted Monday . Cameron praised the contribution made by Hague . `` I 'd like to pay an enormous tribute to ( Hague ) , who is standing down as an MP at the next election , '' Cameron tweeted Monday night . `` Until then , I 'm delighted he 'll remain my de facto political deputy , play a key campaigning role and be Leader of the House of Commons . '' Cameron confirmed Tuesday that Philip Hammond would step into Hague 's shoes at the Foreign Office . Hammond , who has been serving as UK defense secretary , is seen as a critic of the European Union . Cameron has promised a referendum on UK membership of the EU by the end of 2017 if he is still Prime Minister after the 2015 election . His Conservative Party currently governs in coalition with the Liberal Democrats . Cameron has called for EU reform but was recently thwarted in his efforts to block the appointment of Jean-Claude Juncker as the next president of the European Commission , taking office later this year . That appointment is expected to be confirmed in a European Parliament vote later Tuesday . Another casualty of the Cabinet reshuffle was veteran MP and former chancellor of the exchequer Ken Clarke , who is a strong pro-European voice . `` Ken Clarke has been a political Titan for more than a generation . His wise and trenchant views will be missed around the Cabinet table , '' Cameron said via Twitter . While foreign secretary , Hague took a prominent stand on the issue of ending sexual violence in conflict , teaming up with Hollywood star and U.N. special envoy Angelina Jolie to call for global action . The pair co-chaired a summit in London last month which brought together representatives from nearly 130 countries . Hague said on Twitter that he would continue to lead the UK campaign to end sexual violence in conflict as Cameron 's special representative . He added , `` I 'm proud we now have a restored @ foreignoffice , revived alliances , a new course in Europe , and stronger UK leadership on # humanrights . '' Hague has previously published two books on British political history . CNN 's Steve Almasy contributed to this report .
NEW : Hague 's successor will be Philip Hammond , until now the UK defense secretary . William Hague had served as UK foreign secretary for the past four years . Prime Minister David Cameron announced a major government reshuffle on Monday . Hague will be leader of the House of Commons until next year 's general election .