Only if you live in Kirkcaldy & Cowdenbeath in Fife, Scotland (where Gordon Brown is the Labour Candidate); Witney in Oxfordshire (Cameron, Conservative) or Sheffield Hallam (Clegg, Liberal Democrat)! In Britain we chose a national government by electing candidates in each of the 650 constituencies. The prime Minister is NOT directly elected, as the US President is.
Party identification remains much greater in the United Kingdom than in the United States. I would love to imagine that the 15,895 people who put a cross next to my name on their ballot papers in Blaby voted for me - but I know that most of them were voting Labour. They wanted Tony Blair to be the Prime Minister more than they wanted me as their MP!