Liberal Democrat leader Tim Farron has revealed he used to have a picture of Margaret Thatcher on his bedroom wall as a teenager.

In an interview with ITV's Tonight programme, Farron admitted the former Tory prime minister was one of several "weird icons" of his youth, even hinting his interest in the Conservatives resulted from a teenage crush.

"There was a young woman, let's be careful what I say, who when I was about 15 or 16 had a soft-top Morris Minor and she was a young Tory and so I was somewhat taken aback by her, but frankly not by her politics," he told ITV in an interview to be broadcast on Monday evening (8 May).

Farron, 46, denied being a Conservative supporter as a boy and dismissed claims from an old friend that he had an "I Love Maggie" sticker on his textbook.

"No, I don't believe I did," he said.

He continued: "I had all sort of kind of weird icons that I was into. I had a Carl Sagan photograph above my bed who was of course the great – I guess the human voice of Nasa.

"I had pictures of strange sort of left-wing politicians. I remember I had a Mrs Thatcher picture. I had a John F Kennedy picture. I had a Jo Grimond [former Liberal Party leader] picture."

Last year, Farron refused to rule out the Lib Dems returning to coalition with the Conservative Party, telling IBTimes UK: "Any serious politician who rules out going into power isn't a serious politician."

But since the general election announcement, he has U-turned and says his party would not enter a coalition with the Conservatives or Labour.

His wide-ranging interview with ITV also saw the Lib Dem leader give his views on immigration, abortion and homosexuality.

Recent weeks have seen the politician dogged by questions over his stance on homosexuality given his Christian faith, although he has since said he does not believe gay sex to be a sin.

The ITV programme revealed the Lib Dem leader's friend, known only as Ian, had come out to Farron as a teenager.

"He's the first person I came out to as being gay when I was 19, he absolutely just took it in his stride, it's never been an issue and he always absolutely makes me feel welcome and my own personal experience is that he isn't homophobic and that he is absolutely liberal in his values," Ian said.

Farron said he was "genuinely moved that he trusted me".

When asked about whether it was a mistake not telling the public sooner that he didn't think gay sex was a sin, the Lib Dem leader said: "I think real judgement is believing that one's personal and private faith is just that.

"I think most people believe that in politics and in all life people's personal faith is just that and it is not right for us to force that on other people not to be forced to be in a position where one has to talk about the intricate details of one's faith. But I am determined to build a country, to lead a country where LGBT rights are absolutely central to it."

Farron also gave his views on abortion, saying his faith did not mean he wanted to change the law.

"Can I just be very clear on that I have a very strong view that when abortion takes place it should be safe and it should be legal – and I support the law as things stand. Again, what one believes in one's personal private faith is just that."

On immigration, the anti-Brexit MP said he was against setting an upper limit figure for immigration, claiming it would "make it very hard for British business to do what's good for British business".

"I'm not saying no figure but you set an artificial figure you will break it and you'll end up telling British business what is good for British business.

"And I think immigration's been a blessing to this country not a curse – there are few politicians who've got the guts to say that, I will," he said. "But we have controls on immigration [in] this country and too often politicians are too happy to use immigration and immigrants in particular as an excuse for their own failures and I will not do that."

The interview with Farron is the first in a series of half-hour ITV programmes ahead of the general election. They will go on to feature Theresa May, Jeremy Corbyn, Paul Nuttall, along with Nicola Sturgeon, Leanne Wood and Caroline Lucas.