In 1978 I had sex with a man for the first time. I was 17 and the encounter took place in a public toilet. Not something to shout about perhaps. But it's a moment I was reminded of by John Nicolson’s Bill to pardon gay and bisexual men historically convicted of sexual offences that are no longer criminal.

We weren’t caught and so I wasn’t convicted and neither was the man I had sex with, not for the meeting with me at least. Had we been, it would have been for an offence which would still be regarded as criminal today, because of where the activity took place. It would remain unpardonable, in the terms of Nicolson's bill. Whether that should be so is a moot point but it doesn't excuse those who stood in his way.

It was a fleeting moment and I’ve no idea of his name or how old the man was. We didn't speak. I’d guess he was in his thirties but he may have been younger. When you’re 17 everyone looks quite a lot older. It sounds so sordid, doesn’t it? A public toilet. An anonymous rendezvous. Even without any more detail some people reading this will probably find it a tad disgusting. And glamourous it wasn’t. But for me, it was a seminal moment (no apologies for the pun) and one which I’ve never had the slightest regret about.

I’d known I was probably gay for about two or three years. I didn’t have a language for it, let alone any role models. I had absolutely no sense that there was anyone at my school who was experiencing similar thoughts. Some rock stars, notably Bowie, had provided a glimpse of a non-heterosexual hinterland. But the dominant images of the time were of camp men who were the subject of ridicule. This was the era of Grayson and Inman.

The toilet was on a green on the edge of the small town where I went to school. I’d stopped there a few times on the way home and realised from some lewd graffiti on the wall that it was a place where men might meet for sex. On the day in question, I was running home after a training session during the school holidays.

I can’t really remember whether I actually needed a pee but I can remember the sense of nervous possibility that entering the place created. In the absence of any alternative at all, this was somewhere I might get the chance to find out what the thoughts I had been having meant. I was a lone explorer in a world where my emergent sexuality was a great taboo. That much I knew. So if my voyage involved sex in a toilet, well so be it.

The meeting itself was, perhaps inevitably, pretty unsatisfactory. Yet it was enormously powerful because it confirmed something I’d hardly dared to acknowledge. I was sexually attracted to men. In the succeeding months, I went back to the toilets a few times in the hope of more but to my disappointment, there was never anyone there. It was to be another two years before I touched a man again by which time I was at university, the place where I met men who identified openly as gay for the first time. It was still a crime because I was under 21.

Goodness knows what would have happened if we’d been caught in the toilet that day. Judging by the reaction I got a few years later when I first came out to my parents, there would have been hell to pay. But for the man I met the outcome, would, of course, have been far worse, a conviction for gross indecency at least. And worse still for him, at 17, I was under the age of consent for sex with a man.

Would he have known? Possibly. But I was six foot three and starting to shave. It wasn’t term-time so there was no obvious sign that I was still at school. However, I’d almost certainly have looked under 21, the discriminatory age of consent at the time. And yet it was an entirely consensual affair. I was every bit as much the protagonist as him. And for that reason alone the disgraceful tactics used last week outraged me.

The filibustering, which apparently took place despite earlier promises of support for Nicolson’s Bill, was justified on the basis that it might automatically pardon men who had been guilty of sex with a minor, non-consensual sex or of an offence which would still be a crime today including sex in a public lavatory, known colloquially as cottaging. He rightly protested that it would not have.

And yet as my long ago but not forgotten experience shows, criminality and sexuality were pretty mixed up. these were days when the only place to be gay was in the margins of society. You were a minor until you were 21 and even then a hotel room was deemed not to be private. For young men like me, coming of age was distorted by the law and into the shadows we went.

Even if they might have reservations about what we did and where we did it, everyone participating in the debate last week knew that the law of gross indecency, which dated back to Victorian times, had been used to seek out and persecute gay and bisexual men. I had come to know that in very clear terms myself just a few months after the encounter in the toilet when I spent a week at the local paper for work experience.

That week, as most weeks in those days, the paper covered the court proceedings affecting men caught having sex in public toilets. In just a few short paragraphs lives were shattered. The space between words was incalculable and yet the chat around the newspaper room was characterised by a potent mix of righteous indignation and homophobic banter; they had it coming to them these perverts. I kept my counsel of course but shuddered at the thought that I now knew they were talking about people like me.

There were no reasonable grounds for opposing John Nicolson's Bill last week, let alone engaging in such wantonly immoral parliamentary tactics. It would not have pardoned men who had been involved in the kind of activity which I resorted to as a teenager nor the men who found themselves the subject of reports for cottaging in local newspapers. I think a way should be found to do that. But the Bill would have been a step forward.

My lack of personal shame doesn't extend to arguing that sex in public toilets should be permissible today. But it happened then because men had few, if any, other options. So at least the Bill would have framed my early explorations in a different context. Some will argue that's as much as I can hope for now.

However there are those whose were convicted and whose past crimes would remain unpardonable for whom the consequences have been public, real and long lasting. For them Nicolson's Bill will not be enough. They will argue that more should be done and I agree. But I don't point the finger at Nicolson and others who have put the spotlight on past injustices. And it doesn't justify the tactics he was met with.

When it comes to tackling terrorism we’re told that homophobia is unwelcome intolerance which has no place in our 21st-century British value system. Yet when it comes to offering some dignity to some of the men whose lives were shamed and ruined we’re met with political tactics which have no place in that value system at all, let alone in any modern democratic legislature.

Homophobia. You may think it’s all over. But on the latest evidence from Westminster, it isn't yet.