LONDON, ENGLAND - JUNE 19:  Britain's Prime Minister David Cameron and NATO Secretary-General Anders Fogh Rasmussen (not pictured) hold a joint news conference in Downing Street on June 19, 2014 in London, England.  During his visit to the United Kingdom the Secretary General will meet with British Prime Minister David Cameron, British Foreign Secretary William Hague and British Defence Secretary Philip Hammond in preparation for the 2014 NATO Summit in Wales.  (Photo by Luke MacGregor/WPA Pool/Getty Images)