A spokesman for Defence Secretary Philip Hammond has denied claims that he compared same-sex marriage to incest.

It had been alleged the Conservative MP made the comments to students Joe Rayment and Jack Saffery-Rowe last Friday during a visit to the University of London Royal Holloway’s Egham campus in Surrey.

On Monday afternoon, a spokesman for the defence secretary said: “It’s untrue. He didn’t equate equal marriage to incest.”

Earlier, when asked by PinkNews.co.uk to clarify the remarks concerning incest and why it had been alleged that he had used the word, Mr Hammond personally emailed PinkNews.co.uk: “The discussion ranged very widely and was not limited to same sex relationships.”

Joe Rayment, a 21-year-old third-year physics student, told the Guardian that Mr Hammond had not actually used the word “incest”, but had raised the issue when he was challenged about his opposition to equal marriage.

Mr Rayment, told the Daily Telegraph that Mr Hammond “definitely” made the comments attributed to him.

“We had a meeting with Philip Hammond,” Mr Rayment said. “During the meeting I asked him what right does the state have to tell two people who love each other that they can’t get married?

“He said, ‘Well we don’t allow siblings to get married either’.

“We then said that incest and homosexuality are not comparable. He never took it back and he never apologised. I found what he said incredibly offensive.”

MPs will vote on the second reading of the government’s Marriage (Same Sex Couples) Bill on 5 February.