A few years ago, on a trip to Vancouver, I found myself sat at the back of a sightseeing trolley tour. The driver was an amiable older man, who reeled off the history of the city with knowledge and affection: dropping in the occasional insight and story from his own life as he pointed out the famous sights and local landmarks. It turned out that he had the little finger missing from one of his hands. He explained that he had been involved in an accident, and the finger had been violently bent backwards. When healed, the finger was still bent at an awkward angle backwards. Not only was this an inconvenience, but – he chuckled – “people thought I was... ahem, you know?”

The occupants of the trolley laughed. Even I smiled. We all knew what people must have thought. If a man's pinky finger sticks out backwards, he might be gay. Eventually, the driver decided it would be easier to have the near-useless finger cut off: hence the missing digit.

The trolley tour came to an end. Its occupants disembarked, entertained and educated by our history tour and the amusing anecdotes. The driver had meant no harm. It was only later, when I reflected upon the his story that the significance of what he had said sunk in. Apparently he had had a part of his body amputated because he didn't like people thinking he might be gay. Yes, that was only part of the reason, but still, it seems to have been a factor in his decision.

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I was reminded of this when I read a recent article by Graeme La Saux. In The Times at the beginning of the month, the former Chelsea football player – who, like the driver on my trolley tour, is heterosexual – reflected on how, in the early 1990s, he found fellow players and fans questioning his sexuality. The taunting began after it was discovered that he read The Guardian and had been on a touring holiday around Europe with a fellow footballer friend.

"The homophobic taunting and bullying left me close to walking away from football. I went through times that were like depression. I did not know where I was going. I would get up in the morning and would not feel good and by the time I got into training I would be so nervous that I felt sick."

Le Saux stuck things out, but the memories of his experiences – in particular, the vicious taunting he received from some other players on the pitch, have not dimmed.

"The abuse I had to suffer would be multiplied a hundredfold for a player who was openly gay. The burden would be too much."

This weekend, London's Southbank will be hosting a three-day cultural festival entitled 'Being a Man'. I have been invited to participate in a panel discussion on 'Being a Gay Man', in which one of the subjects for discussion will be ‘the level of oppression felt by gay men.’ That gay men – and women – continue to be oppressed is without doubt. Were this event to take place in Russia, I could be arrested for publicly discussing my sexuality. Was it Uganda or Nigeria, I could face a lynching or several years’ imprisonment. I consider myself fortunate to live in the UK, where laws exist to protect me from such persecution. However, although homophobic oppression may be less visible in the United Kingdom, like environmental pollution, it remains in the atmosphere. And, as the examples I offered at the beginning of this piece, I don't believe homophobia just oppresses gay men: it affects straight men too.

You think those examples were extreme? Have ever modified your behaviour – perhaps opted to wear something different, or chosen not to reveal you like a certain song or film – purely because you didn't want people to think... 'Well, you know'. If so, then you have reacted to – and become a victim of – homophobic oppression. To be revealed as gay, or thought of as gay, still elicits a fearful response in far too many people. It's a fear that we pass on to the next generation when we tell our children what toys they can or can't play with, or what colour possessions they can own. When little boys are told to ‘be a man’… there is only one type of man that the rebutter has in mind.

When so many gay people are the victims of truly vicious homophobic oppression, why should I be bothered to highlight that suffered by straight people? It’s because the 'them' and 'us' mentality around homophobia is part of the problem. Homophobia affects everyone – not just gay people.

Those who introduce homophobic laws believe such laws affect only ‘them’ – the LGBT community. If you are heterosexual, it can be so easy to think that such laws are nothing to do with you – that they’re something happening to other people in another country. But the suffering faced by a section of society will inevitably affect society as a whole.

Three years ago, I interviewed Roger Crouch, who had just won a ‘Hero of the Year’ award from Stonewall, at the LGBT charity’s annual Equality Awards ceremony. Roger’s son, Dominic, aged 15, killed himself after experiencing bullying at schools – some of it homophobic in nature. In the months after his son’s death, Roger talked at schools about the dangers of homophobic bullying, but he remained devastated by his loss. A few days after our interview, he took his own life – a double tragedy for his surviving wife and daughter.

If you think homophobia and homophobic oppression have no effect on you, think again.

The ‘Being a Man’ festival at the Southbank runs from Friday 31 January-Sunday 2 February. http://www.southbankcentre.co.uk

If you've been affected by bullying, you can contact The Samaritans for support