British Prime Minister David Cameron delivers a speech on 'the future of the European Union and Britain's role within it', in central London, on January 23, 2013. Cameron on Wednesday promised to hold a referendum by 2017 giving British people the choice of staying in or leaving the European Union if his party wins the next election. AFP PHOTO / BEN STANSALL / AFP / BEN STANSALL        (Photo credit should read BEN STANSALL/AFP/Getty Images)