When I was 21, I lived with a cult for a year. It was a commune really, a tight-knit group of Christians, but I’ll call it a cult because it was in Texas and for special occasions we all wore white. There were other cult markers, too: we had a charismatic leader; the younger kids were home-schooled; and, to my great excitement, one (now ex) member wrote a book after she left: I Can’t Hear God Anymore: Life in a Dallas Cult.

That I ended up there is a testament to the dangers of showing off. All those endless questions after finals, all those inquiring adults: ‘And what are you going to do now? What’s your plan?’ Well, I had no plan. Every pathetic half-plan faded before it formed, lost against the black enormity of the future, so I took to telling everyone I was off to America. ‘To write a book,’ I said airily, ‘about religious cults.’ I thought it made me sound interesting, and that everyone would soon forget.

Lies create their own momentum; I didn’t know that then. No one forgot and so, come late summer 1996, I had no option but to go. I found myself on a plane bound for New York with a wad of travellers’ cheques and an electronic typewriter. I stayed with my kind, sad American godfather in upstate New York, and after the leaves turned yellow I bought a tinpot car and headed south.

To my great relief, a school friend, T, joined me for the journey and so together we buffeted down the interstate; together we shivered through the night in the tin pot’s semi-reclining front seats, and together we approached Dallas, Texas, one October afternoon, without any place to stay, but upbeat and trusting in fate. Oh, the happy days before iPhone.

The Trinity Foundation was our only Dallas contact, recommended by a film director. They were Christians, he’d said (ugh, we thought), but they were also investigators, (cool, we thought), keeping an eye on the corrupt ‘health and wealth’ preachers across the state. So there we went, 5640 Columbia Avenue, east Dallas, and there I stayed, on and off, until the following autumn.

It has been 20 years since I left, which is why it’s on my mind, but also because since that first ‘exposé’, several former members have declared themselves victims of the Trinity ‘cult’. So I’ve been thinking back: am I a victim, a brave survivor? Is there a book here for me, too? I’ve searched myself, mind and soul, and all I’ve found, I’m afraid, is a sort of homesickness for my cult, and an admiration for grown-ups who never succumb to normality; who, against all the prevailing currents, try to live their faith.

The Trinity Foundation, I discovered after a few days there, was at heart a Bible-study group. Up we got at 7 a.m. to listen to our leader teaching, then off to work. The great aim was to live like 1st-century Christians: communally, honestly, helping out the poor and homeless. Some members worked at normal jobs, others for the community itself. The earners handed over 10 per cent of their income, which funded the rest of it, I suppose. I examined them closely for signs of brainwashing: forced smiling, facial tics, stress. For the most part, they seemed to me to be normal adults, a bit fatter perhaps, but funnier, too.

The group’s founder and leader, Ole Anthony, was the controversial one: a tall and bony man with vertical hair and a gift for spin. Ole led the Bible studies and took it upon himself to deflate any growing egos in the group. ‘Get over yourself,’ he’d say to uppity members. Quite right, I often thought, laying low at the back. He’s a bully, say his critics now, a narcissist. He was definitely the sort of magnetic figure who should worry a mother, though as it happens mine had more pressing concerns. ‘Mum,’ I’d say down a crackling landline, ‘I’m living in Dallas with a cult of personality.’

‘Yes darling, are you brushing your teeth?’

Ole packed a punch, it’s true, but then most leaders do. His focus was on living the gospel, which did not allow for egos. And if mind-control had been his game, then it was a great mistake to take in the homeless. Since their beginning in the 1970s, Trinity members had offered their spare rooms and sofas to down-and-outs. This, for them, was the definition of loving your neighbour. For me, it was an education, a dismantling of the myths you’re taught when young: work hard and you’ll succeed; helping others is its own reward. Addicts, the elderly, the bankrupt: everyone who came to stay brought their own brand of chaos. The homeless boy we saved set fire to a house. Ex-junkies often stole away at night with the TV to sell it for crack.

Every morning at Bible study, Ole would say: ‘Die to self. Take up your cross.’ This pissed me off. I spent long hours smoking and puzzling away at it. It sounded sick, almost suicidal. But by the end of my year, I half-understood. If you’re in it for yourself, for the feelgood factor, you won’t stay for long.

One day in July, when the humidity was unbearable and seatbelt buckles hot as branding irons, we all went on an outing. There was the inevitable barbecue, messing about and a swimming pool in which members were ‘re-baptised’ (an annual tradition). Ole, with an eye for drama, stood in his bathers and submerged members one by one. Feeling a part of things, finally, I took my turn and thought perhaps I might surface a believer. I remember being pushed under, the look of the pool’s surface from below; the twisting light coming closer. Then my eardrum burst and I spend the rest of the day not reborn but deaf.

I remember also, quite clearly, my thoughts on the homeward-bound plane from Dallas to London. I had had a terrific year,I decided, despite writing not one word. I wasn’t so daft as to call myself a Christian, I thought, but I had caught a glimpse of what it’s like not to spend your life squirrelling away treasure, but to live your faith. There’ll be so much more of this in the wider world, I remember thinking, excited for once by the future. Two decades later, I’m not quite so sure.