LONDON: British Prime Minister David Cameron’s Conservative Party has overtaken the opposition Labor Party in a poll on voters’ intentions for an election on May 7.

The Opinium poll for the Observer newspaper published on Sunday put the Conservatives on 35 percent compared to 33 percent for Labor, the first time Cameron’s party has overtaken Labor in that polling series since March 2012. It follows a Guardian/ICM poll which put the Conservatives at their highest level in that series since May 2012.

Most other opinion polls since the start of the year have had Labor narrowly ahead or level with the Conservatives before what is shaping up to be one of the most unpredictable elections in modern British history.

On Sunday, Labor leader Ed Miliband, whose party faces a threat from a surge in popularity for the Green Party as well as strong support from the Scottish National Party, said he was appointing former Labor Deputy Prime Minister John Prescott as an advisor on climate change.