Conservative MP Sir Edward Leigh has called for his party to “apologise” for legalising same-sex marriage, saying a future Labour government would have introduced the measure anyway.

Mr Leigh, MP for Gainsborough, told the BBC: “We [need] to reassure our traditional voters that we really are conservative”.

The devout Catholic previously opposed civil partnership legislation and campaigned against the removal of Section 28, the law which banned schools from teaching students about homosexuality.

He voted against the same-sex marriage act for England and Wales last year.

The MP said: “I think it was a great mistake to bring in gay marriage. I think some future Labour government would have done it anyway. It wasn’t necessary for a Conservative government to do it. But it’s done now [and] we are not going to undo it.”

Sir Edward added: “I would have thought a senior Conservative minister could at least apologise to our traditional older supporters, who value their traditional old-fashioned marriage [and say] we were sorry that we upset their core beliefs.

Repeating the point he concluded: “So I don’t agree with gay marriage, I voted against it, it’s done now, but I would have thought somebody at the top of the party could apologise for the hurt it’s caused.”

Sir Edward, who was knighted last year, also called for an “informal” Tory pact with UKIP