Britain’s ruling Conservatives were set to lose hundreds of seats in local polls yesterday that will go some way to measuring the threat the surging anti-European Union UK Independence Party (UKIP) poses to their hopes of re-election in 2015.

Even in towns like Ashford in southeast England, which has returned a Conservative MP to the national Parliament at every election since 1945, surveys suggest UKIP could win up to one fifth of the votes.

History shows Britons often use mid-term council elections to punish their favoured party for perceived failings by temporarily forsaking it only to return when it really counts.

But polling data shows UKIP, which wants to radically tighten immigration rules into Britain, is luring Prime Minister David Cameron’s traditional supporters away.

That trend risks splitting the centre-right vote in 2015, making Cameron’s task of beating the main opposition Labour Party even harder.

The Conservatives, the senior partner in a two-party national coalition, trail Labour by up to 10 percentage points in opinion polls, but they are banking on an economic rebound by 2015 to lift Britain from its torpor.

If a national election were held today, Labour would win.

“I’ve been a Conservative all my life but I’m going to vote for UKIP,” said Bill Newton, 76, a retired businessman, out shopping in Ashford’s futuristic tented mall. “I want the Conservatives to get the message that they need to change.”

More than 2,000 council seats in largely English rural counties and in one Welsh area were up for grabs yesterday. One national parliamentary seat is also being contested in northern England where UKIP hopes to come second to Labour.