The 83-year-old first-time novelist was inspired by his escape from the Japanese occupation

Mark Cheng is pondering whether it is ever too late to publish your first novel. “I read about an old woman recently,” he says, “who released a book at 91.” Then he pauses and rebukes himself. “I shouldn’t be describing her as old. I’m 83 and have just published my first novel.”

It’s hard to credit it. Seated at a café in London’s St Pancras Station, where he has just arrived from his family home in Bedford, Cheng’s face is strikingly youthful. He lifts his legs to squeeze them under the squat table between us with all the agility of a man half his age. Indeed, the only concession he appears to make to anno domini is when he pauses, mid-sentence, struggling to recall anecdotes about his family and friends.

And, to be fair, he does have plenty of decades to scan back over. Cheng was born in Hong Kong in 1930, the son of a university official who converted to Catholicism from Anglicanism because of his strong belief in authority.

Cheng moved with his family to China in 1942, following the Japanese occupation, and then lived in India, Hong Kong and, since the late 1950s, in the UK, where he has raised his family and worked until retirement in 1990 as a history teacher.

The writing bug struck early. He remembers a ten-minute piece he wrote, aged just 14, about the interrogation of the Jesuit Reformation martyr, St Edmund Campion. Words, he admits, have been a passion ever since, although “more off than on”.

Mention of the Jesuits brings us to another chapter in Cheng’s long life history. Educated at a Jesuit school in Hong Kong, he joined the Jesuit novitiate in 1949, straight after graduating, but left after just 16 months. His departure wasn’t, he recalls, entirely his own choice.

“I didn’t want to give up that easily, but in those days they didn’t take anyone they didn’t want. I would have welcomed two, three or four more years to work at it…”

He leaves the thought hanging.

Does he still have regrets then? He thinks for a moment or two, and then breaks into a smile. His barrister daughter, he says, is a member of what was until very recently the Jesuit parish in Wimbledon, south London.

“Whenever I go with my wife to stay with her, we go to Mass there. Sometimes I look up at the altar and I do have a feeling it would have been nice to be a Jesuit priest.”

That time in the novitiate, though, wasn’t wasted in writing terms. It has given him indirect inspiration for the central character of his novel, Father Paul’s War, set in China in the 1930s and 1940s, covering the Japanese invasion and then the post-World War victory of the Communists under Mao Tse Tung.

“Fr Paul’s not me, he’s fiction,” Cheng protests. And indeed Fr Paul is a Cistercian not a Jesuit. But then Cheng adds, “ a lot of what you put in comes from you”. Fr Paul also struggles with his vocation.

Cheng talks of all his characters with fond familiarity, as if they are sitting at the next table. He even voices his own writerly reluctance in making a decision as to whether Paul chose the religious path or marriage. At least this time, it was Cheng’s choice.

“It caused me a lot of thought,” he admits. “When I created Margaret [Fr Paul’s girlfriend], I almost fell in love with her character. A friend of mine who read the book said Margaret was a very generous woman to put up with Paul”.

Was that dilemma between the vocation to religious life and the vocation to marriage something he had also experienced himself? He smiles at another memory.

“I knew a girl, when I had already decided to become a Jesuit novice. It was my last year at school. I was getting to know her, but I kept putting up a defensive screen, because I had made my decision. It was nothing as dramatic as in the book though!”

His own marriage – his wife is also Hong Kong Chinese – came several years after he left the Jesuits. But does he ever wonder what he would have done if a married priesthood had been permitted?

“In the last 12 months or so, I have found myself really looking at myself,” he replies. “I think I would not have been able to be a monk. I couldn’t commit myself to it.” He chuckles. “I’m too fond of my own personal freedom.”

That’s not quite answering the question. The Eastern-rite churches in Catholicism have long allowed married priests, while in more recent times there have been married convert Anglican clergymen who have become Catholic priests.

“That happened to my dentist,” he says. “Deep down, I was brought up as an old-fashioned Catholic. I found it hard to believe someone can call themselves a Catholic priest and not be celibate. But my experience with my dentist has made me change my mind. What’s wrong with being married? It’s up to the man. There’s a place for celibacy, but for secular priests. The choice should be for the individual.”

The personal choices that confront Fr Paul are, however, only one of the storylines in this engrossing and polished novel. It is also an exploration of the fate of the Catholic faith in China during a tumultuous period in its history. Fr Paul has joined a Cistercian monastery in the hills outside Beijing in the 1930s, but it then comes under sustained pressure, first from the Japanese invaders, and then for the resurgent Chinese Communists.

The monastery was a real one, its fate a story Cheng first heard at school. “In my last year there, one of our teachers, a Fr Sheridan, told us about this Cistercian monastery, Our Lady of Consolation, which had been destroyed by the Communists. And that has somehow stuck in my mind all these years.

“It was only when I asked a friend of mine, some years later, what he knew if anything about this monastery, and if anything had been written about it, that he told me to read Thomas Merton’s Waters of Siloe. It is his telling of the story of the Cistercian order. In it he gives over 10 pages to the story of the destruction of Our Lady of Consolation.”

As befits a former history teacher, Cheng took that fragment, then researched the story thoroughly, and uses it in his novel. Up to and including a visit to its ruins?

“Oh, no, I have never been to China,” he says, as if it is a bizarre suggestion that he should have. So he’s never returned home?

“Yes, to Hong Kong, several times, but Hong Kong isn’t China.” And on that point he is adamant. What stops him going to China proper, then? “I don’t like Communists,” he says simply.

And the novel provides plenty of reasons for such an emphatic statement. The new Communist rulers of China in their pathological dislike of religion razed Our Lady of Consolation to the ground. Its monks were tortured, abused and murdered. Father Paul’s War tells the stories of these martyrs.

The main character, though, manages to escape and undertakes a perilous journey all the way across China to join fellow Cistercians. Some of them have managed to get to Hong Kong, then a British colony, where they have re-founded a monastery.

It is a long march told in panoramic detail. How did Cheng manage to create such a convincing picture of a countryside he has never visited?

“You’re told things,’ he explains, as many a novelist before him has had to when faced by the same question of fact against imagination, “by your parents, by newspapers. That’s how I know what I know.”

So what of the current strained relationship between the Vatican and the Chinese authorities, with government-approved bishops and priests operating there as well as those loyal to Rome? The latter face imprisonment for their refusal to cut their ties with the Pope.

“It is difficult,” Cheng says. “Pope John Paul II tried very hard to open the way for discussion with the Chinese Patriotic Church. But it’s very hard. Many mistakes were made.”

Among his contemporaries, he recalls two – “one was called Mark like me, and one Benedict” – who were both consecrated bishops as young men, by older Vatican-appointed bishops, fearful that the Communists would wipe out their church and anxious to preserve a thread of continuity. Both suffered long periods of persecution. But another of Cheng’s generation, called Joseph, is a priest in the Chinese Catholic Patriotic Association.

“And he is, as far as I know, a good priest ministering to his congregation.”

Today’s China, though clearly doesn’t hold quite the same fascination for him as the China of the 1930s and 1940s. “Occasionally I read reports about what is going on now. And I hear stories. Most Catholics, I think, are for the recognition of the officially approved Chinese hierarchy.”

His next project will take him even further back into Chinese history. “I’m struggling,” he confesses, but makes plain that his age isn’t the problem. This Indian summer as a novelist is clearly nothing but a bonus.

“No, I’m writing a historical novel, set in about the third century BC, about a well known Chinese story.” So what’s the struggle? “My Chinese,” he jokes, “was never very good”.

Father Paul’s War by Mark Cheng is published by Alliance Publishing Press on August 31 at £8.99