Darren Purse shakes his shaven head and smiles at the suggestion that there is something quietly heroic about his words in this interview. His surprising readiness to discuss one of the oldest taboos in football does not, after all, carry any grand agenda. The 33-year-old captain of Sheffield Wednesday, a former England Under-21 international who has played in the Premier League and for six different clubs, is not about to launch a campaign against homophobia in football.

Instead, after hearing the happily chaotic sound of his children returning home from school with his wife, Lindsay, Purse talks honestly about a subject that almost every other footballer in this country seems to avoid. "I've thought about it," Purse says, "and there can't be anything worse than living a lie your whole life. But, as a captain, what would I do if a 21-year-old team-mate came to me and said: 'I don't want anyone else to know about this but I think I'm gay'? It would be hard to know the best advice to give him.

"I'd like to say: 'Life's too short and you need to be happy.' It must be horrible going to work and hiding such an important part of yourself. Imagine doing that every day in a career that lasts 15 years. But I'd have to think very carefully before I advised a young footballer to come out."

It is striking that a footballer who is often dismissed as a journeyman of the English game, as an ageing League One centre-back, should speak so intelligently and sympathetically about an issue that frightens administrators, managers and players far more powerful than him. "I'd probably say he'd have to feel strong and thick-skinned enough to handle the pressure and abuse. His personal life might be better but would that outweigh the risk to his football career? It's not a nice thing to say but if you're a gay footballer wanting to come out you'll end up thinking of Justin Fashanu."

Purse was a 13-year-old Millwall supporter, and playing in the same youth team in east London as Lee Bowyer, when Fashanu became the first and, so far, last professional footballer to come out in 1990. Nine years earlier Brian Clough had signed Fashanu to replace Trevor Francis, who would buy Purse when he managed Birmingham City. Clough was outraged to discover that Fashanu was "a bloody poof" and apparently barred him from training at Nottingham Forest.

Fashanu's eventual public declaration of his sexuality received a similar reaction. His horrified younger brother, John, a key member of Wimbledon's Crazy Gang, offered a newspaper exclusive: "My Gay Brother is an Outcast." Eight years later Justin Fashanu hanged himself.

"I'd just become a teenager when Fashanu came out," Purse says, "and it caused a big stir. And football 20 years ago was nowhere near as big as now. I'm not proud of it but I remember going to Millwall and seeing people throwing bananas at John Barnes. It was awful – and fortunately that doesn't happen now. Black footballers are really respected in England. So attitudes can change. But the difference is that black players can't hide their skin colour. They're black and they're rightly proud. But if you're gay you can hide it and keep it bottled up. That's why, if a footballer was brave enough to come out, it would have to be someone like Alfie – nearing the end of his career."

Gareth "Alfie" Thomas is Britain's only high-profile gay sportsman. Purse's friendship with the former record try-scorer for the Wales rugby union team, who switched to league soon after he came out last December, has encouraged him to speak openly: "It was very brave of Alfie. He comes from a working-class background and you get bought up with this tough-man mentality. But you won't find anyone tougher than Alfie. He hid his sexuality for so long and he's far happier now.

"I was at Cardiff City and got to know Alfie. We're also both managed by Emanuele Palladino and I knew he was coming out. People respect him even more now. But the fan element, and the media, would be far harder in football. Opposition rugby fans sit together and go for a pint. But there's this hatred between football clubs and the slightest thing gets blown up."

This week the findings of a research study into homophobia in football were released by Staffordshire University. The researchers had been prompted by Max Clifford's assertion that he advised two well-known Premier League players to conceal their homosexuality because "football remains in the dark ages – steeped in homophobia". The Staffordshire academics suggest, in contrast, that 80% of fans are "relaxed" about the emergence of gay players. And yet their sample quotes from supporters are familiar. Beyond the claim that "gays can't play football – fact" the murky logic of the bigoted fan argues that homophobic abuse is merely "stick" aimed at the opposition.

Purse, who has taken his share of vitriol during a 16-year-career, seems more certain. "Football fans are a breed unto themselves. I've played for two really strong sets of supporters – the Zulus of Birmingham City and the Soul Crew of Cardiff. And I'm a Millwall fan. God knows how they would react to a gay player. Look what happened to Sol Campbell [swamped by homophobic insults whenever he played for Arsenal against Spurs]. Sol got it terrible. He left Tottenham for their bitterest rivals and they thought it was just for money. It was a great career move but Spurs fans had the blinkers on and used their worst gay chants."

Football might be shrouded by sour old rituals but Purse finds hope in the way once rigid attitudes have changed in society. "Forty years ago it was pretty much unheard of for a gay person to live openly. Now there are gay partnerships and gay marriages."

Purse believes footballers are more ready than either the media or many supporters to accept similar change. "If a player came out I think it would be fine in the dressing room. The lads respect each other as players – and people. We'd soon get back to the usual banter and it would be liberating for the player who comes out. But he'd have to contend with the outside world."

He laughs when asked what his team-mates might say if they heard him talking so freely. "The lads probably won't read the Guardian." They could see a mention of this interview on his Twitter page, but Purse remains relaxed: "I'm thick-skinned and why shouldn't I talk about it? I'm comfortable with my own sexuality."

Purse started going out with his wife when he was 15 and they were at school in Bethnal Green. They have been together ever since and so he stands apart from the usual whirlpool of football gossip. "There're always rumours in football. A player might go out on a Saturday night and there'll be a hundred girls around him but he never goes home with any of them. You get whispers then. They say there's 'one' in every dressing room and with the amount of men playing professional sport it can't just be Gareth Thomas who is gay. But I haven't come across one footballer in all my teams who I could say is gay. That shows you how hard gay players must work to conceal it."

Purse is a highly visible presence at the centre of Wednesday's defence and today's home match against Southampton is significant. "It's massive. We were the two favourites to get promoted but after seven games Southampton are 22nd and we're 11th. Earlier this month we played Brentford and if we'd won we would have been four points clear at the top. But we lost that one – and our next two games. We need to start winning. Wednesday are a huge club and for the opening game of the season we got 23,000. That says a lot about this club."

Two divisions below the pinnacle of English football, the famous old Sheffield club are led by a footballer of courage and principle. Purse is determined to help Wednesday back into the Championship and to complete the necessary coaching courses that could lead to a future career in management. But his passion for football has not diminished his wider vision.

"I think the game will get there in the end," he says of the long and furtive struggle for gay footballers. "It seems a long way away but eventually things will change. One day every footballer should have the chance to be true to himself."