In 2009, a few months after the former Welsh rugby captain had come out as gay, a couple of hundred people joined in a homophobic chant at the match he was playing for the Crusaders at Castleford. “It didn’t make me angry, it just made me really sad – and that’s a horrible emotion,” he says. “I can deal with anger. I can release my anger in the game and use it to motivate me. But when something makes you sad … I remember thinking to myself: ‘Why have I gone through all this serious amount of pain … to be standing here, the subject of abuse. Was it worth it?’” It was the worst abuse he experienced on the pitch, but his team-mates supported him and Castleford was fined £40,000.

Thomas retired from rugby in 2011 after a glittering career. He has 100 rugby union caps for Wales (and four from when he switched to playing rugby league) and captained the British and Irish Lions team. He had also become a rare thing: a high-profile, current figure playing in a team sport who had come out.

That day at Castleford did go some way to making rugby a more welcoming sport, or at least highlighting that change was needed. “I didn’t set out to make a change,” Thomas says. “I set out to be myself, but if by being myself I can effect change then … I’m quite motivated by it now, but I remember at the time thinking: ‘If I have to play every single week listening to this, I can’t do it.’”

We are sitting in his lovely cottage in south Wales, only a few miles from where he grew up and a short distance from where he lived with his ex-wife. The house is full of family photographs. He is quick to smile, warm and welcoming. Even sitting on the sofa, Thomas seems huge – shoulders wide as a bear, tattoos covering meaty arms. His dog, Boyo, snoozes on a cushion on the floor between us, having given up trying to steal our chocolate biscuits.

Thomas playing for Wales in 2010. Photograph: Stu Forster/Getty Images

Last week, Thomas and the MP Damian Collins launched a draft amendment to the 1991 Football Offences Act that would explicitly outlaw homophobic abuse at matches (the act currently bans chanting of an “indecent or racialist” nature). He would like to see it brought in across all sports but, as football is governed by specific legislation, it seems a good place to start. The move comes at a time when homophobia in football has been highlighted by events at the World Cup – Fifa fined the Argentine Football Association for homophobic chants by its fans during their match against Croatia; in the qualifying rounds, the Mexican Football Federation was also fined several times for fans’ homophobic chanting. A report by the Fare network and the Sova Center – both international anti-discrimination campaigning organisations – published before the World Cup started, found that homophobic chanting at football matches, along with racist chants, had increased in Russia, which introduced anti-gay laws in 2013. “This is a practice that takes sustenance from state-led homophobia, but has been copied from leagues in western Europe,” the report says.

“I learned when I came out that sometimes [negative events] have to happen to effect positive change,” says Thomas. “I’d like to think that, through what has happened at this World Cup, Fifa will have to sit down and put something in place.”

Should Fifa have taken a stand and said it was not going to hold the World Cup in Russia, where LGBT rights are being eroded? “Without a shadow of a doubt. The fact it’s in Russia, and the fact the next World Cup is in Qatar [where homosexuality is illegal], is mind-boggling. The only [positive] thing is that it highlights the problems that LGBT people still suffer around the world.”

Last year, to mark the 50th anniversary of the partial decriminalisation of homosexuality in the UK, Thomas made a documentary looking at homophobia in football. He had seen the impact the Football Offences Act had had on reducing racism at grounds. “I thought it was interesting because it had never been amended. Society had moved on, but the act hadn’t.” A 2016 survey for Stonewall found that 72% of football fans had heard homophobic abuse at games, and 22% believed it was “harmless” if it was just meant as “banter”. In rugby union, 37% of fans thought anti-LGBT language was simply banter.

Explicitly outlawing homophobia, Thomas says, will provide clarity. “Some stadiums may say it’s not allowed, some may let it pass. Not all games have police at the grounds, not all stewards are brave enough or trained well enough to understand what constitutes homophobic abuse and how to deal with it. A lot of clubs don’t want to ban their fans from grounds.”

Thomas has been trying to have meetings with clubs to see their policies, “see what kind of environment they have for their players in case any are gay, how they view their LGBT fans and the environment they create for them. Unfortunately, this is not at the top of a lot of the clubs’ priorities. I had to go above them all – the clubs, the FA, the Professional Footballers’ Association, the Premier League – to a law of the land rather than a law of the clubs.” There have been attempts to push through change, he says. Stonewall’s Rainbow Laces campaign to raise awareness and support for inclusivity, with rainbow flags, billboards and bootlaces for players and referees, for example, has been increasing its profile in recent years, “but I sometimes think that the progression is so slow that it ends up being an uphill journey to nowhere”.

Thomas, with his dog, Boyo. Photograph: Gareth Phillips/The Guardian

The FA chairman, Greg Clarke, told a parliamentary committee that a Premier League footballer would suffer “significant abuse” were he to come out, adding that he would be “cautious” about encouraging people to do it. (Casey Stoney, the England women’s captain, came out in 2014, becoming the most high-profile active footballer to be open about her sexuality, but no prominent male footballer has come out since Justin Fashanu in 1990.) “For the chairman of the FA to say that is absolutely insane. But, if that’s what he thinks, at least he’s not lying,” says Thomas. “What is important, and this is what I hope this bill will do, is create the environment where, if a footballer wanted to come out, he would be capable of doing it. You have to create an atmosphere in the ground, the changing room and the boardroom. There are some football clubs I have been to, and some grounds, where I’ve thought: ‘I’m absolutely petrified.’ If I had showed any weakness to this crowd or club, then I don’t think I could have survived playing week in, week out.”

Professional sportspeople have sought Thomas’s advice before coming out – the diver Tom Daley was one – but he says he has never been approached by a Premier League footballer. If one did, what would he say? “It would never be my decision [to tell them to come out],” he says. “If I take my scenario, I felt at the time I want to be able to be myself and to know what it’s like to play a game of sport and be 100% in that moment rather than 50% in that moment and 50% worrying about what the crowd are going to think or call me.” Top-flight footballers, he points out, are in a global game. “In 72 countries, it is still illegal to be gay.” A player may be comfortable coming out in the UK, or in much of Europe, but playing in countries where homosexuality is illegal could be an ordeal.

The rugby environment, the changing room, was so different. I started in an amateur era where ‘men were men’

When he was growing up, Thomas’s biggest ambition was to play rugby for his home club, Bridgend. He was 19 when he made his Bridgend debut, while still working as a postman. He had become increasingly aware of his sexuality and was terrified someone would find out. “I was afraid of losing my people, my town, my game,” he wrote in his autobiography, Proud, which was published in 2014. He had his first gay sexual experience at about the same time and was filled with shame. He went on to marry his girlfriend, Jemma – they had been together as teenagers – but he continued to seek out occasional sexual encounters with men. “As my stature grew, as my popularity in Wales grew, so did my fear of being recognised,” he says. “I came to a crossroads many times – do I want a life of being me or do I want a life of a rugby player? I can’t have both.” But the stress of living a lie eventually became too much and he made at least two suicide attempts, one after telling his wife he was gay (they later divorced). Thomas came out to his team-mates some time before going public. It was a big deal for such a well-known professional sportsman to come out and the response was almost overwhelmingly positive, including that of his family.

He doesn’t wish he had come out earlier; more that the environment had been different and he had never had to lie in the first place. “I might have had the strength [to come out], but I definitely didn’t have the environment,” he says. “The rugby environment, the changing room, was so different. I started in an amateur era where ‘men were men’ … LGBT was not even on the radar. I’m still friends with a lot of the players from that era who I felt were that stereotypical rugby player, and maybe I underestimated them because their support for me was huge.”

Would he have been a different player had he been allowed to be more open? “I was always driven by the idea that if people ever found out about who I was then the stature I created for myself within rugby would have to be as relevant as the fact I was gay,” he says. “It was always the driving factor to be the strongest, the fastest, the most skilful. The one thing I never wanted to reveal to people was the one thing that motivated me to try to be the best.” Growing up, he was haunted by seeing representations on television portraying gay men as weak or effeminate. “I’m a sportsman, as good and strong as you, who just happens to be gay.”

A film of his life, which was to have starred Mickey Rourke, fell through, but there is another film in the pipeline produced by Iain Canning, who made The King’s Speech. “I’d like it to empower other people, not just in sport. [There have been] millions of people who have lived through difficult times,” says Thomas.

He occasionally still gets homophobic abuse on social media, but says: “I’ve built my resistance to be somebody who is willing to fight against that. Now I’m not really in an arena where I could be openly abused; where I could feel unsafe. I’m less likely to be abused on the street than I used to be in a football or rugby stadium.”

Nearly a decade on, does he recognise the man who was so ashamed of his secret, and so afraid of exposure, that he was suicidal? “I never forget that time because it gives me strength to do what I’m doing now, but I’m proud of how far I have come. It’s still me and I want to keep remembering it because you only know what it’s like to live when you’ve really known what it’s like to die – and I felt dead in my life. I don’t take any day for granted, I work hard, I’m motivated.”

I can’t spot a single item of rugby memorabilia in Thomas’s house. His mother keeps it, he says (along with all the letters of support and gratitude that people wrote to him after he came out). “That part of my life is gone and I’m really proud of it, but now I have to do something with this phase. I was born and raised to play rugby. I have two parents who are hugely proud of my rugby achievements, but even they say that maybe it was just a platform to give me a voice to do something better, and rugby wasn’t what I was all about. Something else was.”