Nick Clegg, U.K. deputy prime minister and leader of the Liberal Democrats, left, walks with Dorothy Thornhill, mayor of Watford Liberal Democrats prospective parliamentary candidate for Watford, as they tour the site of the proposed Watford Health Campus in Watford, U.K., on Tuesday, March 31, 2015. Polls put the ruling Conservatives and the Labour opposition neck and neck, with neither on course to win enough votes for a parliamentary majority on May 7. Photographer: Matthew Lloyd/Bloomberg via Getty Images