A survey of Tory constituency chairman has found the majority believe the UK Prime Minister David Cameron should abandon gay marriage.

It found 71% should drop the law, while nearly half say local parties have lost members as a result of the plans.

Only 3% say they have gained membership since the Conservative and Liberal Democrat coalition government announced the law, which is planned to take effect by 2015.

Anti-gay campaigners from the Coalition for Marriage conducted the poll, and it found over seven in 10 grassroots members believed gay marriage had damaged the Prime Minister’s standing in the party.

Colin Hart, campaign director of the campaign group, said: ‘What this latest poll reflects is the growing unease amongst grassroot Conservatives about the way the PM is trying to force through this policy without any electoral mandate and without any acknowledgment of the profound consequences this chance will have.’

He added: ‘If the PM continues to press ahead with this deeply unpopular, radical and profoundly undemocratic proposal, then he can expect to pay the price for this at the ballot box.’