Former Stonewall Chief Executive Ben Summerskill has launched an extraordinary attack on the Liberal Democrats, accusing the party of supporting same-sex marriage in a “cynical and opportunistic way”, despite his own u-turn on the issue.

Speaking first to BBC Radio 4 and later to the Observer, where he previously was an Assistant Editor, Mr Summerskill claimed that the Liberal Democrats supported same-sex marriage in order to put a distance between themselves and the Conservative Party in 2010. Mr Summerskill said he was convinced that this was the case because of a comment by former Lib Dem MP Evan Harris who said: “This is great because we put clear blue water between us and the Tories.”

“Note that he didn’t say, ‘hurrah – this is great news for gay couples or for equality’,” said Mr Summerskill. “He made it crystal clear that at that time it was politically opportunistic for the Lib Dems. It is certainly a less edifying view of the politicians involved, but it’s a true view. All you have to do is look at the Lib Dem manifesto in May 2010, even their gay manifesto, and gay marriage doesn’t appear. Suddenly, three months later, there they were quite cynically adopting the policy.”

PinkNews has not been able to find any reports of Mr Harris saying the words that Mr Summerskill quoted. However, The Daily Telegraph reports that he said: “We need to test that new Tory commitment to equality and this one of the areas where we can help Lynne do that”. Mr Harris tweeted today to say: “Ben S[ummerskill] seems to have invented a quote.”

Mr Summerkill’s claims also ignore the fact that the Liberal Democrats were in a coalition with the Conservative Party, which supported a consultation on changing the law on same-sex marriage. He also ignores the support for changing the law by the Lib Dem leader, long before Stonewall supported changing the law.

Answering questions from PinkNews readers in February 2010, Lib Dem leader Nick Clegg said: “Yes, I support gay marriage. Love is the same, straight or gay, so the civil institution should be the same, too. All couples should be able to make that commitment to one another.” While David Cameron, asked if he would support marriage equality responded: “I want to do everything I can to support commitment and I’m open to changing things further to guarantee equality.”

The Conservative Party’s equality manifesto for the 2010 election stated that the party “will also consider the case for for changing the law to allow civil partnerships to be called and classified as marriage.” While it is true that the Liberal Democrat’s 2010 equality document did not include same-sex marriage, its policies are decided by its party conference, which later that year voted to adopt equal marriage as official party policy. Notably Mr Summerskill argued against the party’s then proposed policy at its conference and led the only major LGBT organisation in Britain at the time which did not support marriage equality.

Unlike the clear support that the Lib Dem leader Nick Clegg had given to same-sex marriage, Mr Summerskill had actually argued against campaigning to change the law. In 2009, he told PinkNews: “There are quite a lot of gay and lesbian people who wouldn’t want marriage, and some have explicitly said so.” Adding: “We are one of many, many organisations but at the end of the day, in terms of our priorities, what we’ve always focused on, is absolutely practical hard outcomes which make a real difference to people’s lives. The reality is half the population already call civil partnerships marriage anyway.”

After the Liberal Democrats passed same-sex marriage as official party policy, and after Ed Miliband had told PinkNews that he supported changing the law, Mr Summerskill went to Labour Party conference to say that he would not be “jumped into” supporting same-sex marriage. It was only after the support of the leaders of all three major policial parties to change the law that Mr Summerskill announced that he and Stonewall would support equal rights for gay couples.

Speaking to Radio 4, Mr Summerskill claimed that 10 per cent of the gay community is strongly opposed to allowing gay couples to marry. “Those are people, quite often for example lesbians, who feel very strongly that marriage is a 2,000-year-old vehicle for the subjugation of women, and they don’t like it at all. And I think what we have succeeded in doing, certainly with Stonewall stakeholders and our support has continued to rise throughout that period, is to persuade them that even if they don’t want to get married, other people should be able to.”

International Development Minister Lynne Featherstone who was at the time the Liberal Democrat Minister for Equalities has expressed her revulsion at Mr Summerskill’s most recent claims: “Wow, I’m really upset by that, really upset.” She added that his claims are “absolute rubbish. We are the party of equality and Ben knows that. It wasn’t in the manifesto probably because no one thought it could be achieved – not because of any lack of desire to do it.

“I wasn’t going to raise this, but it has to be said that Stonewall wasn’t in favour of equal marriage and they changed – and I’m very grateful they changed. It is somewhat upsetting to hear that that is his attitude. I thought we were all working together on this. I’m very surprised and disappointed to hear him say that. It’s completely unnecessary.”

PinkNews publisher Benjamin Cohen, who led the Out4Marriage campaign for same-sex marriage said: “Ben Summerskill’s pronouncement is frankly ludicrous and appears to be an attempt by him to rewrite history. The fact is that Nick Clegg, David Cameron and Ed Miliband were all ahead of Summerskill when it came to same-sex marriage. It was a policy that some might say he cynically and loudly supported when it was clear that Stonewall was in danger of being seen to have been on the wrong side of history.”

Peter Tatchell has also joined in the criticism of Ben Summerskill telling the Observer: “An apology would be appreciated. Stonewall does great work but the gay campaign for marriage equality faced an uphill struggle, which was made worse by Stonewall constantly undermining our efforts. Some of the arguments Ben and Stonewall put forward at the time [2010] were quoted by homophobes to justify their opposition to same-sex marriage and this was hugely damaging.

“I am not a supporter of the Liberal Democrats, but on the issue of same-sex marriage the party took an early position, while Stonewall did all it could to sabotage that position. It is unbelievable really.”

Mr Summerskill resigned as the CEO of Stonewall earlier this year. He was among the guests on Ed Miliband’s table at a fundraiser for the Labour Party on Wednesday evening and was a former Labour councillor.