A poll of parliamentarians has found overwhelming support for a free vote on gay marriage.

The poll, conducted by ComRes for the Coalition for Marriage, found that 81 per cent of MPs were in support of a free vote.

Tories were most strongly in favour (94%), followed by 72% of Labour MPs. More than half of Lib Dems (56%) agreed that there should be a free vote on the issue.

Colin Hart, campaign director of the Coalition for Marriage said: “This poll will make uncomfortable reading for David Cameron and Nick Clegg who continue to want to force through these undemocratic proposals regardless of what those who elected them say.”

According to the poll, MPs report strong opposition to the proposals from their constituents. Asked about correspondence on the issue, nearly three quarters of MPs (74%) said that they had received more letters opposing changing the law, than in favour.

When asked whether legislation to redefine marriage should go ahead "irrespective of the balance of feedback" from the Government's consultation on the issue, just 26% of MPs agreed.

Forty-four per cent said the legislation should only proceed if the there was “broad support for the measure”.

Mr Hart said: “It shows a growing sense of unease at the way redefining marriage is being handled, not least how the concerns of ordinary people have been ignored, which explains why our elected representatives are receiving so many letters on the subject.”

He expressed concern that supporters of traditional marriage would not receive adequate protection.

“Mr Clegg and Cameron have failed to say how they will protect those who support the current definition.

"Legal and constitutional experts have warned that the current proposals are a lawyer’s charter and could see individuals who do not support these changes, including teachers, chaplains, public sector workers and even parents ending up in court. I am sure that this is not the Government’s intention.”