UK elections kick off with parties neck and neck

London - British Prime Minister David Cameron will on Monday ask Queen Elizabeth II to dissolve parliament, kicking off formal campaigning for one of the most unpredictable UK elections in decades.

Both Conservative leader Cameron and opposition Labour leader Ed Miliband have already set out their battle lines for 7 May, focusing respectively on the economy and the state-run National Health Service (NHS).

Campaign buses will criss-cross the country and candidates with colourful rosettes from their respective parties will go door-to-door in an election in which every last ballot could be key.