There were many heroes of the Repeal the Eighth campaign, and Graham Linehan was certainly one of them. Looking back at that campaign, what made the most difference to public opinion were the people willing to tell their stories of unexpected or unhappy pregnancy, and abortion. There were so many stories, and so many circumstances. So many tragedies, unacknowledged until then. It became impossible to believe that abortion wasn't an issue that affected every single one of us.

Graham Linehan and his wife Helen shared their story - a termination following a diagnosis of fatal foetal abnormality at 11 weeks - as part of a campaign led by Amnesty International. At the time, Linehan said: "I have always been very proud to be Irish but I am embarrassed by Ireland's abortion laws. This is just something you can't be proud of. It's barbaric."

The vote carried, the Eighth Amendment was repealed. But for Linehan, anyway, a new fight began almost immediately. This was largely fought online, over something that a majority of people are possibly still confused about - the rights and demands of transsexual people - and the allegation was that Linehan, also a vocal supporter of the Marriage Equality referendum, was transphobic and a TERF (trans-exclusionary radical feminist).

The battle raged, mainly on Twitter, for the best part of a year, and, last October, civil proceedings were brought against Linehan by a transgender lawyer, Stephanie Hayden, of defamation, libel and harassment, based around the alleged misuse of gender pronouns and 'dead-naming', which means referring to a transsexual person by their birth name. Hayden claimed that Linehan allegedly published a series of tweets "deliberately misgendering" her by using her previous male name.

At the same time, Linehan was contacted by police after Hayden reported him for transphobia. This was reported as Linehan having received a harassment warning. "That is not true," he says now, very firmly. "A harassment warning is a very real thing, and I never received one."

Last week, Hayden dropped all charges against Linehan, leaving him free to talk about the experience.

Is he relieved the case has been dropped? "Well yeah," he says. "It's been hanging over me for half a year now so it has been quite tough. It's also been tough because while I've been quiet about it, the other party hasn't. It's good that it's over. It's not a nice thing to be sued, although I always thought we'd be exonerated."

But let's go back a bit. Just how did Linehan, writer of the evergreen and hilarious Father Ted as well as Black Books and The IT Crowd, go from well-known "woolly liberal" in his own words, to a figure of hate for some within the trans community?

This started, it seems, with someone digging up a series of unconnected tweets, some very old, and putting them together to paint a particular kind of picture: "Someone did one of those multi-tweet threads: Here's all the things Graham Linehan said that prove he's a TERF and transphobic," Linehan explains. "I looked at them and I thought, there's nothing wrong with any of these things - every one of them is sympathetic to people with gender dysphoria and is thoughtful about the effects that trans ideology has, and is always about the ideology, not trans people. I thought, there's nothing to be ashamed of in that, so I'm going to fight this rather than accept the idea that I'm transphobic. I'm not transphobic and never have been."

And so instead of explaining or apologising, he decided to react. This was in the aftermath of Repeal the Eighth. "When I was fighting for Repeal of the Eighth, I felt I was fighting for women, for women's rights, and I felt, I'm not going to stop doing that now because these people think it's the wrong cause. You have to be consistent." And, he points out: "The weird thing about this debate is that I've made so many trans friends through it. But they're not the 'right' kind of trans friends according to the ideologues."

There are many, many strands and elements to the debate - all complex, highly emotive, carrying anger and hurt, and not easily resolved - but the fundamental boiling point seems to be the phrase 'trans women are women', and what, exactly, that means. For Linehan, it goes like this: "I think trans women as women as a courtesy is something that I'm fine to follow. But trans women as literally women, is something I object to. And I think everything comes off that statement." It is the "literalism" of that statement that he refutes. "If you're talking about gender - which I take to mean how you present and how you want to be seen - have as many definitions as you want. I've seen a list of something like 150 possible genders. That's fine. But it gets into trouble when you talk about there being more than two sexes."

However the transgender community would argue that the phrase "sex assigned at birth" (replacing "biological sex") is a more accurate and respectful way to acknowledge the process of sex assignation that occurs at birth through a perfunctory look at external anatomy. It might not be possible in all cases (e.g. intersex) to identify an individual as male or female at birth. For trans people, assigned sex may differ considerably from gender identity.

For many though, the question isn't so much what, as why? Why did Linehan fight this cause so vigorously? "I decided to start talking about it, and to keep talking about it, because everyone else who spoke about it was getting silenced very quickly and I thought if I refuse to be silenced, if I keep going, then I'll show other people that there's nothing to be scared of. That there's no shame in being critical of gender ideology."

Fundamentally, it comes down to what he sees as bullying. "I decided to enter this because I noticed that women who entered it were being fired from their jobs, were being harassed, were being driven off Twitter. And the things they were saying were very simple feminist concepts. The temperature of debate was being kept so high that no one could talk about it. So I wanted to go in and try to amplify the voices of people who I'd seen abused and insulted. I felt they weren't being heard. I wanted to help the women. I saw all this happening and I thought, 'I'm going to be a nail, and they're not going to bend me easily'."

Given it all to do again, he would, he says, do things a little differently. But only a little. "I did not take into account the effect that the constant harassment and smearing and vilifying and suing would have. And it has been tough."

It is not, he points out "helping anyone not to talk about it, because there are obvious conflicts, and those conflicts need to be resolved. I think hopefully, bit by bit, we'll be able to chip away and show - there is going to be a conversation about this. When we say 'debate', it suggests we're taking opposing positions. There are lots of trans women who agree with me. Those people are considered traitors by the group of politicised trans people. So it's not so much a debate as a conversation in which we work from a shared position of scientific truth. These things need to be discussed to help women, to help trans people. The only people who can be harmed by such a conversation are the bad actors who are steering the conversation towards polar opposite positions, and trying to intimidate people. Those people who are concerned about the conversation becoming civil, they will try and make sure that we can never move past this point."

There are, he rightly says, "so many personal stories - everyone knows someone who is trans. But that doesn't mean we can't talk about this. There are many well-meaning people who wrote to me believing they were standing up for their friends. They have been told by mainstream trans-activism, which is really extreme trans-activism, that there are no ways to talk about this, because if you do, you're debating it, and there is 'no debate'. They have had it drilled into them that anyone who steps from the path, immediately has to be shut down".

Being sued was not something he expected, although "I knew the person was litigious. I certainly didn't expect the police to call. That happened the same weekend".

At first, Linehan believed the phone call from the British police was good news. "I was asked, 'do you know Stephanie Hayden?' I said 'yes', and I thought, brilliant, because I had previously told the police - there's this person who might be bothering you, because I knew that was their modus operandi, and I wanted to give the police some background. So I thought, brilliant, they're calling because they're going to do something about it. But no."

Linehan was asked if he could stop talking about Hayden on Twitter. "'Could you not just block them?' I said I already have, a long time ago." At the time, Linehan said, "The police asked me to stop contacting someone I had no intention of contacting. It was a bit like asking me never to contact Charlie Sheen".

That phone call, like the legal letter, and the many angry tweets, are all, Linehan feels, part of an attempt to create smoke, regardless of whether there is fire. Although the case has been dropped, Linehan's legal costs, he says, are £28,000. Some £7,000 came from anonymous donations, but that still leaves him with a hefty legal bill. At first, his intention was to go to court, but "if I had gone ahead with the hearing to get the case struck out, it would have cost me another £7,000 or so".

That money, or some of it, came from an unusual source. "Around the time this whole thing started, I had cancer [Linehan announced he had been diagnosed with cancer in June 2018]. To our surprise, we found that we had insurance for it, and I said to Helen that, as my gift to myself, I want to use some of this money as a way of fighting this. Because I think it's an important fight and I really hope that something good comes of it."

He also says, with a laugh "I always wonder if my decision to get into this conversation was affected at all by the fact that I was on morphine coming out of the operation [after diagnosis, Linehan had a testicle removed]. That was around the time I thought, I'm really going to start talking about this now. And I always wonder, was that because I was on morphine? Because I just couldn't feel any pain! It's not out of the question!"

He is now, he says, "going to back away from the whole conversation for a while. I feel I've done enough. I've proved my point, I've taken the hits, and now it's really up to other people to step up, and I hope they will. I do realise," he says, "that I was perhaps not the best person to try and break open this debate, being a straight white male, but I do think that it has had an effect."

He has, of course, other fish to fry, namely Pope Ted - The Father Ted musical. "We just did our first mini run through of it," he says, "and it went very well. The way we look at it, it's the final episode of Father Ted."

He is also at the "starting stages" of a few other projects; "for a writer, life is more important than reading, and I've had so much life over this last year. Maybe too much life! I think the good thing is that there's definitely a store of material I can use. This fight has been so weird, there have been so many ups and downs; I feel it's all gone into a storehouse. And the other thing is I've met so many wonderful people from all walks of life. I was in a bit of a media bubble before this, but now I know social workers, policemen, teachers - everyone is affected by this debate in different ways, and I've made so many friends through it."

Does he regret getting so involved? "No. It was the right thing to do. I've always hated bullies. I was bullied in school, so I just get angry when I see it happening, especially to a whole group of people, and I saw it happening to women. In the end, I can sleep happily because I did the right thing."

Sunday Independent