There is a "strong case" to be made for introducing gay marriage, according to a Tory frontbench spokesman.

John Bercow argued that reviewing the Conservative's position on gay rights was a "litmus test" of the party's willingness to change.

Gay marriage as a term emotionalises the whole issue

John Bercow

There are already strong calls from Tory modernisers, including ex-minister Steven Norris, for the scrapping of Section 28, the law banning local authorities from promoting homosexuality.

Mr Bercow, the shadow work and pensions minister, said that while the Tories had no plans to introduce the civil registration of gay marriages, there were intellectual and ethical arguments for such a move.

'Powerful case'

He told a fringe meeting at the Tory conference in Bournemouth that a "strong case can be made".

"Gay marriage as a term emotionalises the whole issue," he said.

"I think there are good arguments in favour of civil registration of partnerships and I think a strong case can be made.

No-one wants pupils exposed to unsuitable material on gay sex, says Bercow.

"There was a bill in the House of Lords. It has fallen by the wayside. The Conservative Party has no plans to introduce such a scheme.

"But if you are arguing about the intellectual or ethical attractions of having a system of the kind a very powerful case can be made."

Duncan Smith's challenge

Mr Bercow heaped praise on Conservative leader Iain Duncan Smith for his pledge to review the party's support for Section 28.

"I regard it as a litmus test of whether the Conservative Party is determined to change," he said.

"It is an absolutely essential issue for that reason.

"I don't think Iain for one moment will duck the challenge. It is essential that we meet that challenge."

Mr Bercow stressed that no-one wanted pupils to be exposed to unsuitable material on either gay or straight sex.

Clear signal

But he poked fun at claims that young people would be encouraged to experiment by looking at educational material.

He added: "Come on, let's get rid of these demons and grow up and come to terms with the world as it now is."

Ministers will attempt to repeal Section 28 when Parliament returns, but some right wing Tories - including former party chairman and shadow deputy prime minister David Davis - have reportedly threatened to resign if Mr Duncan Smith backs the government's position.

However, modernisers in the party believe that if Mr Duncan Smith supported the government's bid to scrap the measure, the Tories would be sending out a clear signal that they have changed.