Tim Farron, the evangelical Christian leader of the Liberal Democrats, has again avoided answering whether he believes homosexuality is a sin.

In a wide-ranging interview with GQ magazine, where Farron admitted he would not be remembered, he dodged questions on homosexuality. However he insisted one of the reasons he became a Liberal MP was to support LGBT rights.

"I'm not a religious leader; I'm a political leader," he said.

"I think that everybody is utterly equal. People should be free to love who they want and marry who they want. But I don't go making theological pronouncements.

"One of the reasons I joined the Liberals was because of lesbian and gay rights. Friends of mine were gay and I saw how they were treated and bullied. I want a society where people are valued for who they are."

The 45-year-old was previously asked three times whether he thought gay sex was sinful by Channel 4 News' Cathy Newman, shortly after he became leader following the Lib Dem's disastrous election result.

The full interview in GQ's March edition, which is available from February 4, covered his legacy as leader and his opinions on Boris Johnson, whom he labelled "the Donald Trump of the United Kingdom".

Farron, who is MP for Westmorland and Lonsdale, also admitted he would not be remembered in the future.

"There's no point in worrying about how you'd like to be remembered at all," he said.

"I would like to have made sure I did things that made a difference to people's lives. The whole point of winning elections is to make a difference. I see a whole bunch of people in this place who, whether they say it or not, are trying to leave a legacy – they like the idea of holding office, not making a difference."