UKIP has accused the government of ‘picking a fight’ with religious people in Britain over plans for equal civil marriage saying the issue is ‘in the domain of the church and other faiths’.

It has also claimed that “any criticism” of gay marriage on religious grounds could risk being designated a hate crime under the government’s proposed equal civil marriage rights.

Party spokesman David Coburn said it supported civil partnerships but that the prime minister “seems to be saying that marriage is something else”.

“If so, it is clearly in the domain of the church and other faiths – and it is none of government’s business to meddle with it.”

UKIP has two seats at Westminster in the House of Lords as a result of Tory defections but none in the House of Commons. It has 12 MEPs.

Coburn continued: “It seems that, through some kind of political correctness, David Cameron is picking a fight with the millions of people whose religious faiths do not recognise same-sex marriages. That, in our view, is an aggressive attack on people of faith, and an act of intolerance in itself.

“In addition, if the government does legislate in this way, we believe that any criticism of same-sex marriage which may be expressed by someone on the basis of their faith could be classified as a ‘hate crime’. That would be a grotesque assault on people’s freedom of conscience.”

The Prime Minister remains committed to the introduction of civil marriage equality in this Parliament.

UKIP welcomed Roger Helmper MEP’s defection from the Conservatives last week. Helmer made headlines after a blog post praising the “brilliant” comments by Scottish Catholic leader Cardinal O’Brien at the weekend that gay marriage was a “grotesque subversion of a universally accepted human right” and questioning whether incestuous marriages would follow.

Helmer, who once described the Catholic church as ‘systematically paedophile’ wrote on his blog: “Archbishop Keith O’Brien also makes the point, quite reasonably, that once you start to tamper with the institution of marriage, you get into some very murky water indeed. If two men can be married, why not three men? Or a two men and a woman?

“He could have gone further. Why not a commune? If two men have a right to marry, how can we deny the same right to two siblings? Are we to authorise incest?”

UKIP’s leader Nigel Farage said Helmer’s defection “sends a message that people are taking UKIP very seriously”.