Liberal Democrat MP Stephen Gilbert has joined those who have condemned former Stonewall boss Ben Summerskill for suggesting that the party was “cynical and opportunistic” in its support for same-sex marriage.

Ben Summerskill made the remarks in a BBC programme about gay rights, to be broadcast tomorrow on Radio 4, and also in yesterday’s Observer newspaper

Mr Gilbert told PinkNews that he thought Mr Summerskill was attempting to “change” events that took place leading up to the passage of the Marriage (Same Sex Couples) Act in England and Wales.

He said: “This is, frankly, a not very subtle effort at the rewriting of history on this important debate. We should be clear on this, the Conservatives, Liberal Democrats and Labour all supported equal marriage before Ben Summerskill’s Stonewall did.

“Indeed, when I proposed the policy to Lib Dem conference in September 2010 it was in the face of opposition from Stonewall who claimed it would cost billions and that many people in the community didn’t support it.

“I said in that speech that ‘It should not be for me as a Member of Parliament to lobby Stonewall to support equal marriage for gay and lesbian people, it should be for them to lobby me.'”

Going on to commend Stonewall for its efforts in other areas of LGBT  life, Mr Gilbert said the comments by Summerskill were “sad”.

“Stonewall has done a huge amount for the LGBT community but on this issue they were out of step and behind the curve. It’s a bit sad that Ben, who has made an enormous contribution to public life, is making these rather squalid efforts to change the facts of history and sully those who helped to bring about equal marriage.”

The Deputy Prime Minister Nick Clegg has also criticised Mr Summerskill for his comments, saying that he was “sad and disappointed” at the attempt to “divide” the LGBT community on this issue.

Mr Summerskill resigned as the boss of Stonewall last month after 11 years at the helm of Britain’s largest gay rights charity.