My father was a bus driver for thirty years and one of my favourite childhood “treats” was to be taken into the bus depot to sit in one of the buses when it went through the huge automatic washer. (It was the 1970s and there were no Playstations). So buses were a source of fun to me, and an occasional annoyance when they turned up late. But who knew that buses were one day going to become great big political tools in culture wars over religion and sexuality? In 2008, atheists paid for London buses to be branded with the slogan “There’s probably no God. Now stop worrying and enjoy your life.” This prompted a counter-campaign a few months later by the Christian Party who plastered “There definitely is a God; so join the Christian Party and enjoy your life.” Who’d be a bus driver these days? Not only do you have to put up with drunks who won’t pay and teenagers playing their iPods out loud but now you’re part of a propaganda machine, possibly driving round messages that you deeply disagree with.

And now we’ve had Round 2 of the Bus Wars. First, Stonewall paid for London buses to carry adverts that said “Some people are gay. Get over it!” And then, a Christian group called the Core Issues Trust booked two weeks of adverts that said “Not gay! Post-gay, ex-gay and proud. Get over it!” But after complaints, Transport for London have scrapped the advertising campaign, which as the French say, was de trop.

Can people change their sexuality? I doubt it. I believe that sexuality is a lot more fluid than society would have us believe, and that many people who identify as straight or gay actually have the potential for bisexuality. I suspect that even a lot of ultra-heterosexual men would happily oblige if it was David Beckham doing the asking. Our society doesn’t like blurred boundaries though – we’re all supposed to be in neat little tick boxes, so bisexuals often get overlooked or wrongly dismissed as lying closet cases. A lot of us like to “fit in”, and so we have a tendency to suppress parts of our sexuality that other people disapprove of. But that doesn’t mean that those parts vanish – just like being asleep doesn’t mean you’re dead. Ex-gay ministries try to get gay people to suppress stronger aspects of their sexual identity through prayer and “counselling”. Such people, in their intense desire to reject a part of themselves that other people have stigmatised, may eventually claim to be “ex-gay” but I’m not convinced. Stick em’ in a room and show ’em gay porn, and I’m pretty sure they’ll respond just like any other gay person. Ex-gays are just miserable gays who don’t get to enjoy sex or Bette Davis movies.

Tellingly, Dr Robert Spitzer, a psychiatrist who published a study in 2001 which claimed that in rare instances gay people could change their sexual orientation, has recently retracted the claim. In the past, groups like PFOX and Focus on the Family have used this study to help justify ex-gay programs. Spitzer is no homophobe – he campaigned to have homosexuality removed from the list of mental disorders in 1973, and now that he’s 80, he’s worried that his 2001 study would tarnish his legacy. His study looked at what people who had undergone ex-gay therapy said about the therapy, but that didn’t “prove” that the “therapy” worked.

What I find most notable about the ex-gay bus advert though, is the term “post-gay”. Where did that come from? And what does Core Issues Trust mean by it? The term “post-”, so beloved of 1990s social sciences academics is one of those buzzwords that people often use when they’re trying to appear clever. At the Urban Dictionary, “post-gay” means either 1) that gay people define themselves by something other than sexuality, although they still view themselves as gay and care about gay rights. Or 2) Someone who is excessively gay. I’m inclined to view it as closer to the first meaning – for me, in a post-gay society, sexuality just isn’t an issue any more – it will be as unremarkable as whether you prefer coffee or tea or neither or both (we don’t see politicians screaming that coffee drinkers shouldn’t be allowed to get married or religious groups trying to make people only drink tea). Sexual preference just won’t matter, and as a result people won’t necessarily feel as committed to a particular identity for their entire lives. All those straight people who have bisexual potential will be freer to realise that potential. Here’s a recent quote by Paul Iacono, an astute 23 year old actor on the MTV series The Hard Times of RJ Berger, which sums up the post-gay perspective: “I believe that in 100 years, none of us will be having to identify ourselves as gay, straight, bi, or otherwise. Sexuality will be a more fluid thing”.

I take it when the Core Issues Trust use the term “post-gay” they aren’t using it in this utopian sense of sexual fluidity, or the sense of being “too gay”. I guess that like Humpty Dumpty in Alice in Wonderland, when they use a word it means just what they choose. But it does suggest a bit of a “fail” in the campaign, because not everyone will understand “post-gay” in the way that they intend it.

I’d like to suggest a new Bus campaign. Let’s not waste time with advertising slogans. Instead, why don’t we sponsor a bus to drive everyone in the Core Issues Trust on a one-way trip to Old Compton Street. I’m sure they’d make lots of interesting new friends and have a lovely time. Because, really, they could do with a lot of making up for lost time.