NEWCASTLE-UNDER-LYME, ENGLAND - MAY 02: British Prime Minister David Cameron launches the Conservative Party's European and local election campaign durng a speech at JCB World Logistics Centre on May 2, 2014 in Newcastle-under-Lyme, England. During his speech to workers and guest at JCB he promised to "make sure" UK voters get a referendum on whether to leave the European Union. (Photo by Christopher Furlong/Getty Images)
