It is May 1989, the Pinters throw a soirée for Daniel Ortega, and a most celebrated novelist takes pity on an unfamous young journalist

Mine was the face that didn’t fit. Everyone else who had gathered on a golden Sunday evening in May 1989 at the London home of Harold Pinter and Antonia Fraser was immediately recognisable: Melvyn Bragg, Bianca Jagger, David Hare, Ian McEwan, Rosanna Arquette, Peter Gabriel. We were assembled under the auspices of Arts for Nicaragua to welcome the Sandinista president Daniel Ortega, who duly swept up into the quiet square in a limo with his police outriders, and then in his khaki uniform and sunglasses stood out impressively among us in the genteel front room.

I, on the other hand, stood out for all the wrong reasons. I was neither a pillar of the arts establishment nor – with my too long hair – one of the Special Branch officers present. Perhaps I should have started refilling the glasses.

He looked into the distance as he introduced himself, making no assumption that I would know who he was

My invitation had come because, as a young editor of the Catholic Herald at the time, I had noisily embarked on a pro-Sandinista crusade. Pope John Paul II may have disapproved of them as too Marxist for his Polish tastes, but with four priests in the government and a rapid expansion in literacy, education and health care, they seemed to me to be living out gospel values.

As, I discovered, did another guest at the party. Out on the terrace at the back, standing all alone, was an elderly man in an unseasonal tweedy jacket. His green eyes were red and rheumy and his face ghostly pale – I learned later that he had cracked a rib in his hotel room hours earlier and had almost not come – but he was unmistakably Graham Greene.

He continued to look into the middle distance as he introduced himself. It was no affectation, just shyness. He made no assumption that I would know who he was.

As a convert to Catholicism in his youth, and thereafter a novelist preoccupied with themes of sin and redemption, he was one of the few guests at the party likely to know what the Catholic Herald was when I explained that I wasn’t a waiter. Indeed, he said he knew it well, smiled as he recalled his own dealings with it in the distant past and gave his blessing to going against the official Church line on the Sandinista government. Perhaps, he suggested, he should take out a subscription.

Too quickly we were called back inside for the speeches. He was standing directly behind me in the doorway as we listened. As soon as there was a pause, I planned to turn and ask him for an interview. When I did, he had gone, silently and leaving no trace.

Martin Luther: Catholic Dissident by Peter Stanford is published by Hodder on 18 March at £20. To order a copy for £17, visit bookshop.theguardian.com