Between my first kiss and my first A level there came Trotsky. I am sure I would have met him sooner or later, plastered against the wall in a student union bar or on a street corner hiding behind a petition. But he came to me on a sunny day in Hyde Park. It was 1984; the year of the miners' strike, the IRA bombing of the Grand Hotel in Brighton, and Ronald Reagan's victory in the US presidential elections. I was 15 - a self-important teenage vegetarian who felt that all was not quite right with the world.

I had spent most of the day wondering around London with a Socialist Workers Party banner for company, protesting against the visit of the South African president, PW Botha. I had been avoiding the eyes of paper sellers and policemen, when a young man with acne caught me unawares and offered me a copy of Young Socialist. I bought it, read it in less than five minutes - all the articles were basically the same "Thatcher is horrible, miners are great, socialism is even better" - and thought little more about it.

A few weeks later I pulled the paper from the bottom of my bag, wrote to the editor and asked if I could join the revolution with much the same degree of forethought as others in my peer group applied to join fan clubs. I was bored. It was something to do. And there would probably be girls there too, so, who knows, I might even come by a second kiss.

Given the range of anti-social behaviour available to a hormonally besieged adolescent, there were worse things I could have turned my attentions to than the overthrow of capitalism. I would be lying if I said that I was aware of precisely what I was getting into. I knew I was joining some kind of socialist outfit. I suspected it was the younger section of the Labour Party - as it happened it was the youth wing of the Workers Revolutionary Party. This was not a problem for me. After all, if you're going to go into politics at that age you might as well get some cred and join something nobody's ever heard of.

When I discovered they were Trotskyists this did not bother me much either. I didn't really know what Trotskyism was. I scarcely knew who Trotsky was. The leader of the Red Army who had been ousted and later executed in exile by Stalin had, it turned out, left a legacy for those who supported socialism but could not stomach the Soviet Union. I knew him better as Snowball from George Orwell's Animal Farm.

In my naivety I presumed that, since socialism was underpinned by the notion of solidarity, those who believed in it would club together - especially given that they were relatively small in number. I didn't know at the time that there were at least 57 varieties of hard-left party, some with less than 57 members in total. How could I know that there was a significant difference between the Revolutionary Communist League of Britain (RCLB - Maoist) and the Revolutionary Communist Party of Great Britain Marxist-Leninist (RCPGBM-L - pro-Albanian)? In short, I didn't know very much. But then I didn't have to.

The WRP credo was fairly straightforward. Britain in 1984, they believed, was more or less at the same stage as Russia in 1916 - a nation on the brink of revolution. All that was needed to push it over the edge was a general strike. If we could get everyone out together, we could bring the nation to a standstill, form some soviets, replace the police with a workers militia and then Bingo! - capitalism would be dead before you could say Fourth International.

The simplicity of the thesis was a great source of comfort. The party was providing such a comprehensive and unwavering world view that I felt I would never have to work out anything again. It provided a reason for everything that was bad - from the famine in Ethiopia to racist policing - about capitalism. For every problem there was only one solution - revolution. Every issue could be shoehorned into this single transferable analysis, it seemed.

Concerns with details of policy, from taxation to nuclear disarmament, were little more than micromanaging. This sense of self-confidence, bolstered by a similar lack of self-knowledge, lent a distinctly cult-like air to the entire enterprise which, as is the way with cults, I only really became aware of when I'd left. Moreover, the party's uncompromising and often unreasonable stance on most issues dovetailed neatly with the petulant, know-all stage I was going through. If adults ever hit me with the phrase: "You think you've got the answers to everything don't you?" I would think, but never say: "I do actually. Seizing state power from the bourgeoisie and placing it in the hands of the working class as the first step towards a more just world."

I actually pitied those who missed the big picture. I lamented the wasted lives of all the adults who tried to work out their views on individual issues on a case-to-case basis. They were playing dot-to-dot; I had the huge, broad brush. And I was clearly not alone in this. My guess is that there were about 2,000 members, including high-profile actors such as Vanessa Redgrave and Frances de la Tour.

The two main leaders were a Sri Lankan called Mike Banda and a Londoner, Gerry Healy. Their arrival at the microphone during meetings was always met with reverent hush that went beyond the demands of average party discipline. I remember little about Banda's speaking style, but Healy's was unmistakeable. He would shout and scream into the microphone, ranting fluent gibberish. And as he prodded the air with his little finger, his face would get redder and redder until his entire bald head was a small, round pate of scarlet.

Commitment to the party was total. If Britain was about to explode into revolution then it followed that a revolutionary party had to be ready and waiting in the wings. And if the party was to be ready then its members had to be at battle stations at all times, with no excuses and definitely no time off for good behaviour. It meant that everything - births, deaths, marriages, exams, you name it - had to take second place to the preparations under way for the glorious and imminent day when we would not so much inherit the earth as nationalise it, collectivise it and then forbid anyone from inheriting anything ever again.

"The needs of the individual must be subordinated to the needs of the party," chimed the mantra. And it was observed religiously. I spent about three nights a week and at least half the weekend selling papers, attending meetings and organising events.

No birthday, no party, no football match could compete with the demands of the revolution; you simply did not blow out workers' power for a disco or a date. I had a purpose in my life that felt both beyond and above school and parents. Raised under the strictures of Caribbean matriarchy, I felt little need for more discipline in my life but I welcomed my first dalliance with a tradition possessing its own flag (red) and its own anthem (The Internationale). And it was exciting too.

Unusually for the hard left, its youth base was greater among the working class than among students. While there was a general tone of seriousness that affected everyone in the party, life in the Young Socialists - most, on average, only a few years older than me - was a rowdy kind of fun. Not only did it provide an instant group of friends but also a limitless amount of things to do with them. We went to the picket lines in Nottingham, to conference in Blackpool and countless demonstrations in London, all of which meant coach trips and the underage beer-drinking and snogging that went with them.

The older members, however, were apparently a different story. The demands of party work undoubtedly played havoc with their personal lives. A mixture of teachers, council workers and actors, they were, for the most part, a humourless bunch of drones who wore a harried and haggard look which suggested that Armaggedon, not revolution, was just around the corner. They were socially disabled - incapable of talking about anything else but the party because they had long since shut everything else out of their lives.

The fact that nobody else wanted a general strike not only confirmed our cult status, it gave us a messianic edge. Our detractors were either capitalist lackeys - like the TUC - or just plain chicken, like the Communist party, which did actually want a general strike, but only for 24 hours. Thanks to our superior analysis, we were in the possession of a valuable and exclusive truth - the world, as we knew it, was about to end.

However implausible this may seem now, it did not strike me as a completely unreasonable proposition then. Where class conflict is concerned, 1984 was a spectacular year. With bloody pitched battles between the police and pickets at Orgreave, courts sequestrating union assets, bailiffs removing Greenham Common protesters and showdowns brewing between leftwing councils and the government over rate-capping, the idea that parliamentary democracy was in crisis and preferred foul means rather than fair to crush dissent did not seem a fanciful one.

Nor did it seem odd to suggest that, if the miners were going to win, they were going to need the help of other unions. But then I was at infants' school when the miners brought down a Conservative government and had not yet been born when students brought central London to a standstill over Vietnam. I had no idea that I was witnessing a violent but regular episode of the never-ending bump and grind between labour and capital. I would soon learn that, while 1984 may have been spectacular, it was by no means exceptional.

It was nothing like Russia in 1916. For the following year saw not revolutionary upheaval but the biggest defeat the British working class had suffered in over half a century. And by the time the miners went back to work, my revolutionary career was already winding to a close. I can trace the beginning of its demise to a meeting in the party headquarters in Clapham. A red-faced Healy was raging on at the top of his voice and I was watching the clock. I had told my mum I would be back by 6pm. It was already five, I was an hour and a half from home and Healy had only just started.

He finally wound up an hour later and, as I made for the door, a burly man stopped me and told me they weren't letting anyone out during the interval. I explained the situation, but he wouldn't budge. I asked if I could just go out and call home and tell my mum where I was. "The phones around here are bugged, comrade," he said sternly.

"I don't give a shit if they find out that I'm going to be late home," I said. But the doorman was not for moving. I got back at 10pm in tears and in trouble. A few weeks later I went on a weekend school trip to Howarth as part of my A-level English syllabus on Wuthering Heights. When I returned, my mother, who had just about had it with the revolution by this time, told me that the party had been ringing constantly. I called the WRP organiser and received a vicious tongue-lashing.

"You can't just piss off to Yorkshire without telling anyone," he screamed. "Don't you know that the state are picking people up left, right and centre at a time of crisis like this?" "Like who?" I asked. "Never mind who," he shouted, and then delivered a stern lecture on party discipline. By this stage I had had enough. The miners were trickling back to work, the revolution was clearly not around the corner and I was sick of grown-ups playing soldiers. The security blanket of intellectual certainty I had felt when I had joined no longer comforted me. Any suggestion that there was more to politics than class struggle - like race and gender - was met with fierce rebuke.

I was 16 and had already outgrown the revolution. When I did turn up I started to feel harassed. When I refused to go paper-selling one weekend I was accused of being an MI5 agent; when I expressed a casual interest in Fidel Castro I was told that I only liked him because he was black. I started making excuses for not going to meetings and concentrated more on my school work instead. I had been taking an evening course in French and had entered myself for A-levels. I told the WRP that I would need some time off party work for revision. My request was refused. That was the final straw.

I knew that if I didn't intervene at this stage my mother would, and I would rather have taken on the self-appointed representatives of the working class than her any day. I called when I knew the local organiser would be out and told his flatmate I was leaving the party. I didn't sleep that night, so tortured was I by the portentousness of my actions. The next day he came round and lectured me again on party discipline.

Revolutions don't come without hard work, and hard work needed sacrifice, he said. He sounded like a clergyman trying to save a marriage. But he might as well have been talking to the stack of pamphlets that was always sitting in his car. My mind was made up. "I'm leaving," I told him. "Nobody leaves this party, Gary," he said. "They either get kicked out or they die." Given that I am still here to tell the tale, I can only presume that I was expelled in my absence. I had as few qualms about leaving as I did about joining. My nine months in the WRP were a great political and personal education.

In time I would learn the damage of dogma, the power of rhetoric and the fact that politics is not just an extracurricular activity. I discovered that, when it came to debate, shades of grey suited me better than black and white, but that complexity should never be used as an excuse for inaction. And while I never joined a Trotskyist party again, my experience did not leave me with a vitriolic disdain for Trotskyists - although I do think that Trotsky himself would be rather disappointed by many of those who struggle in his name.

In any case, five months after I was "kicked out", Healy would suffer the same fate. Accused by Banda of "cruel and systematic debauchery" after abusing his influence to coerce younger, female party members into bed, and secretly buying himself a £15,000 BMW with party funds, his expulsion made "Reds in the bed" tabloid headlines. Banda's attack coincided with a 180-degree shift in the party's politics, towards Labour under Neil Kinnock. The Redgraves sided with Healy and split to form a separate group, the Marxist party. The hard left had just sprouted a 58th variety.