The Coalition for Marriage (C4M) says David Cameron’s support for equal marriage explains why the Conservatives are expected to perform badly in Thursday’s local elections across England and Wales.

C4M, the UK lobby group that opposes marriage rights for gay couples, has commissioned ComRes to produce a poll – and it shows support for the UK Independence Party at a record high.

Released on Tuesday night it suggests UKIP – a party which opposes equal marriage and only supports civil partnerships – could win a staggering 22% of the vote.

The same poll puts the Conservatives on 31%, Labour on 24% and the Lib Dems on 12%.

Asked: “Does the Coalition Government’s plans to legalise same-sex marriage make you more or less likely to vote for each of these parties in next week’s local elections?”

Just over one quarter (26%) of Conservative 2010 voters responded by saying less likely – with only 9% saying more likely. The results suggest the policy is costing the Conservatives three votes for every one gained.

Coalition for Marriage Director Colin Hart said: “The prime minister has consistently backed the proposed changes to redefine marriage as part of the so called decontamination strategy, but it has not worked. Every section of the electorate are highly sceptical about his motives, believing he is pushing this policy in a cynical attempt to make his party look trendy and progressive. This is the ultimate failure of Blairite triangulation policy.

He added: “As Lady Thatcher famously said ‘if you just set out to be liked, you would be prepared to compromise on anything at any time and you would achieve nothing.’”

The UK Independence Party’s affiliated LGBT group announced yesterday it would be contacting UKIP leader Nigel Farage in the wake of several anti-LGBT incidents involving prospective candidates.

PinkNews revealed last Friday that a homophobic and biphobic election leaflet in Staffordshire was being posted through letter boxes on behalf of Stone Rural UK candidate David Nixon.

UKIP Gloucestershire County Council hopeful John Sullivan, who supports Russia’s attempt to ban gay prides, was also accused of writing on Facebook that regular physical exercise in schools can “prevent homosexuality”.

Speaking to the BBC, David Cameron said on Wednesday that UKIP’s policies and candidates had come under the spotlight and they had to “explain themselves”.

The Conservatives are braced for losses on Thursday, with the 240-plus county council and unitary authority seats they gained in 2009, the last time the seats were contested, potentially looking the most vulnerable.

However, they are still expected to come first in the contest, which is dominated by local ballots in Tory heartlands.