The Liberal Democrat leader, Tim Farron, has confirmed that he does not believe gay sex to be a sin, saying that while he had no wish to “pontificate on theological matters”, he also did not want people to misunderstand his religious beliefs.

Farron, an evangelical Christian, has faced a series of questions about his views on the subject in recent days, prompted in part by an interview two years ago in which, when asked if homosexuality was a sin, he responded: “We are all sinners.”

During a campaign visit last week, Farron insisted he had been misinterpreted. The idea of homosexuality being a sin was “not a statement that I make, this is something I get asked because of my faith”, he told the Guardian.

Speaking to the BBC on Tuesday, Farron clarified his views further to stress that he also does not believe gay sex itself is sinful.

“I don’t believe that gay sex is a sin,” he said. “I take the view though that as a political leader my job is not to pontificate on theological matters. This had become a talking point, an issue, and in that case if people have got the wrong impression of what I think about on these issues, then that’s something it’s right you correct.”

Farron said he was wary of mixing religion and politics: “I’m quite careful about how I talk about my faith,” he said. “I don’t bang on about it. I don’t make a secret of it, either. When I get asked theological questions, which I don’t think many other politicians do get asked, I kind of took the view that it would be better for me to say, this is a matter of theological nitpicking – let’s talk about the politics.

“That’s why it’s really important I answer it clearly today and say, it’s not, and I don’t feel it is.”

Asked why he had not clarified this before, Farron said he had not wanted to “get into a series of questions unpicking the theology of the Bible,” and rejected the idea he had changed his public views because of the election.

“I don’t think people want political party leaders telling them what is and isn’t sin,” he said. “People’s faith is private, and it’s up to them to decide how they make these interpretations. For me, separating faith from politics means you shouldn’t be trying to have a running commentary on these things, and also shouldn’t be trying to impose one’s beliefs on others.”