By Jackie McGlone

LIKE MANY MEN of his generation, Robert Runcie never spoke of his distinguished war record, although in later years he used to say he was probably the first Archbishop of Canterbury since Thomas a[grave accent] Becket to have been into battle. A lieutenant in the Scots Guards, he served in the tanks of the Third Battalion and, at the age of 22, was awarded the Military Cross “for courageous leadership under fire.”

“The only time my father ever referred to the war was if we complained about anything,” recalls his son, James, creator of dog-collared detective Sidney Chambers, hero of the Grantchester Mysteries, who has become a smoking hot heartthrob as incarnated by the divinely handsome James Norton in the spin-off, hit ITV series

Runcie (59) recalls: “If we grumbled, my father would tell my sister, Rebecca, and I that we had never had to pick flies off sandwiches, or towards the end, he said, ‘I don’t suppose you’ve had to bury too many of your friends.’ Shocking sentences like that. But he was very proud of having been in the Scots Guards and he had the gait -- a very straight back -- but he never spoke of the fighting.”

Since he’s confessed that sleuthing Sidney is loosely based on his late father -- although the Right Reverend Lord Runcie never did a priestly Poirot, so to speak -- readers of The Road to Grantchester, a prequel to the six “cosy” Mysteries, could be forgiven for thinking that he has drawn on his father’s war. The novel, which is hugely enjoyable -- “it’s quite old-fashioned, I think,” murmurs Runcie -- begins in 1938, with 18-year-old Sidney quickstepping in London’s Caledonia Club with his best friend’s wee sister, 15-year-old Amanda, who grows up to become an enchanting, bantering beauty.

Five paragraphs later and five years on, Sidney is on a transport ship with the 2nd Battalion Scots Guards, preparing to land at Salerno. What follows is some of the finest writing I have ever read about the sorrow and the pity of war. The battle scenes are conjured so vividly, so viscerally over barely 90 pages that it seems unimaginable that Runcie was not there, reporting from the battlefields of Italy, where Sidney eventually wins the Military Cross for bravery after losing his best friend.

The bulk of the novel is set in peacetime against the backdrop of post-war austerity, poverty and profound social change. It’s a world in which the death penalty still applies, homosexuality is illegal and women’s place is in the home.

Over Earl Grey tea in the graceful elegance of his Edinburgh home in which books definitely do furnish the beautiful room where we’re sitting, Runcie says that he did a huge amount of research into the Second World War but he also had the gift of access to a cache of letters. They were written home by the late Peter Balfour to his wife Diana, in East Lothian. “From the letters I got the sense of camaraderie. The sheer boredom, the moments of terror. They really helped me get an idea of what Sidney went through.”

He began writing the books almost ten years ago. “I always knew there would be six, each made up of linked short stories. They are moral fables because I’m more interested in whydunit than whodunit. I always knew they would cover the post-war years up to 1978, when Sidney is into his fifties. Two reasons: everything changes with Mrs Thatcher and that’s a block to me. [His liberal-leaning father famously clashed with the Iron Lady.] It is much too close to my own experience. The other thing is forensics -- you can’t really be an amateur detective in the age of forensics. You don’t want this vicar hanging around.”

Could Sidney not have become Archbishop of Canterbury?

“I did think about that as a joke,” he laughs. “But that might have been rather too self-indulgent. As soon as anything in the books comes close to my dad, it has to go, although I grant you there’s the fact that Sidney is in the Scots Guards. I honestly thought I was done with him, however, with the final book, Sidney Chambers and the Persistence of Love, though I’ve considered writing his Casebooks. One day perhaps.

“Yes, I was sad to end them because it’s been ten years of living with him. People were always asking me whether he’s my dad. He is and he isn’t. But he’s also me, a version of me even if I’m not a detective. The books helped me to find a style, a voice which I hadn’t had before.” Previously, he’s written four standalone novels and has just finished his magnum opus, The Great Passion, a 90,000-word-long literary novel, about Bach and the writing of the St Matthew Passion.

The Road to Grantchester was not an easy book to write, he confides. Then a woman from the Salvation Army publication The War Cry interviewed him. “I thought ‘I’ll do the usual guff. Sidney is half my dad and half not,’ When it comes to my faith, I’ll quote Thomas Carlyle, ‘a life of doubt enriched by faith.’ Then, ‘Faith is a mystery and I write mysteries.’ Very Anglican fence-sitting. But her first question was, ‘Right, James, I want to ask about your personal relationship with Jesus Christ.’ I thought, ‘Blimey! I can’t really give the glib answer. So I said, ‘It’s a bit on-and-off, to be honest.’ I realised I had been very big on thinking and talking about God and very absent about talking about Jesus. A big absence.

“I began questioning why Sidney became a priest in the middle of a war, or just after. My grandfather on my mother’s side stood up during the First World War and said, ‘There is no God! How can there be in the middle of this hell?’ I wanted to know how you come out of a terrible war with faith. I knew I could not do the Road to Damascus moment but I knew I could do the Road to Emmaus. So faith, Amanda and secrets were the key. We live in such a blurty age now but do we really want to know everyone’s secrets? I thought I knew Sidney’s but it was slippery. I didn‘t know the key element of him -- his faith.”

An award-winning filmmaker and Commissioning Editor for Arts at BBC Radio 4, Runcie, who has a rumpled, bookish air, says that in creating the character of Sidney he found a voice that “somehow has a loving, compassionate humanity that is literate but that also has moments tinged with tragedy, pathos and comedy bumping into each other. Chekhovian moments. Chekhov is my biggest influence. I was brought up in that funny, tragic world -- you know, funerals that would go disastrously wrong. That awkward, rather English comedy of desperation.”

But then Grantchester is not Line of Duty, say, or indeed Happy Valley, in which Norton played a psychopath. ‘We do crime in the series but it does not involve scantily-clad women running away or missing children. There is so much of that on TV -- it’s absolutely terrible! We do the moral stuff around the crime, although my editor at Bloomsbury, Alexandra Pringle, says, ‘These are sermons, James, aren’t they?’ Of course, you write something and only afterwards do you realise what it is, so she’s probably right.”

Sermons or not, the TV series is immensely popular in America, where it fills the gap left by the demise of Downton Abbey. Legions of US viewers are currently avoiding spoilers about the last series, when Norton was replaced by another troubled prelate with a penchant for solving mysteries that are “Morse with morals, an Anglican Father Brown or Barbara Pym with no clothes on.” Sidney is undeniably TV’s sexiest vicar but, in the books, he’s married. “And that’s terribly important to me,” explains Runcie, who has been married since 1985 to renowned radio and theatre producer and director Marilyn Imrie, with whom he has one daughter, writer Charlotte Runcie. Marilyn’s daughter from her first marriage is award-winning theatre director Rosie Kellagher.

“Marilyn and Rosie do drama; Charlotte and I do words, although Marilyn, who is always right, is my first reader,” says Runcie, who was educated at Marlborough College, Trinity Hall, Cambridge and Bristol Old Vic Theatre School, where he “discovered theatre and, more importantly, actresses.”

Both Runcie and Sidney have perfect old-school manners. When I mention this, he says: “James Norton’s the real charmer. He’s very tall, always leans down, almost too close, when talking to people, which apparently Bill Clinton does too. My father did that, although James didn’t know that. It makes people feel that they’re the only person in the room. That’s when Sidney really reminds me of my dad.”

The Road to Grantchester, by James Runcie (Bloomsbury, £14.99).