MANCHESTER, ENGLAND - OCTOBER 07:  Prime Minister David Cameron poses with wife Samantha after his keynote speech on the fourth and final day of the Conservative Party Conference, at Manchester Central on October 7, 2015 in Manchester, England. Mr Cameron has announced plans to encourage developers to build 200,000 new 'affordable' homes for first time buyers. The initiative is set up to secure the homes by the end of the parliament, and is one of the key election pledges of the Conservative's election campaign. (Photo by Stefan Rousseau - WPA Pool /Getty Images)