Camilla — yes, that Camilla — says he is one of her favourite authors, and the multi-award-winning Peter James rather sweetly lists 1967’s Charterhouse School poetry prize on his list of honours and prizes. (These include coveted crime writer awards such as the CWA Diamond Dagger).

James is the author of many standalone novels, translated into 37 languages (including Hebrew). But he is best known for his long-running crime series, starring his fictional Brighton detective, Roy Grace. And now, this weekend Grace hits the small screen in an adaptation of the first novel in the series, 2005’s Dead Simple, and Peter James publishes — in May — his 17th Roy Grace book, Left You Dead.

Sharing almost equal top billing with Roy Grace in the books is James’ beloved Brighton, studded with his intimate knowledge of the Sussex police. But when we speak, it is from the writer’s new home in Jersey, where he and his wife relocated a couple of years ago.

It’s a much better place from which to write, he says, because he was forever interrupted while in Brighton. And it has a good literary pedigree — it was in Jersey, James tells me, that Victor Hugo wrote The Hunchback of Notre Dame.

Behind him, in his study, I can see shelves displaying what look like police caps, helmets and hi-vis security clothing, part of a collection which James has amassed over the years. “My whole office is a police museum”, he admits, telling me he always asks for souvenirs of a local police force whenever he travels on book promotions, often swapping for something he already has.

“Wait”, he says, leaping up, “I’ll show you the creepiest item.” And he returns with a police hat worn by members of a children’s army, which we both agree is really horrible. His ambition, he says, is to acquire a helmet from every country in the world, but he still has some way to go.

It’s taken a long time to get Roy Grace on to television. James has a background in film and TV production and three of his pre-Grace books were made into mini-series in America. “On one of these, I wondered if the writers had even read the book. A bad adaptation can hurt an author’s career, so I’ve always been very careful. I was adamant when I first sold the rights [to the Grace books] that I should have a clause that if I didn’t like the way things were going, I could get the rights back.

“Thank God I did. I got a call in 2008, very excited, to tell me that BBC Scotland wanted to put up all the money. I said, why does BBC Scotland want to finance a TV series set in Brighton?” The plan, James was told, was to relocate Grace to Aberdeen police. This did not find favour. Three years later he received a call from another company which had been looking at the success of Scandi dramas, whose central police officer was often a woman. How would it be, James was asked, if Roy Grace was made female?

Finally, Russell Lewis, who had been working on Endeavour, was lined up to write Grace for ITV. James didn’t want to write the scripts himself because he prefers to work on new books, rather than eviscerate his old ones.

There is an odd link between Dead Simple and Left You Dead, the first and most recent of the Roy Grace books. In Dead Simple, the detective is in mourning for his missing wife, Sandy, who has disappeared without warning. And Left You Dead was sparked by James musing, what if his wife went into a supermarket, and then never came back? That’s the situation for the set-up of a possible murder, investigated by Roy Grace and his trusty Sussex team.

This year’s writing has been hampered by Covid for James, who famously likes to do energetic research. I nearly wrote “undertakes”, a more apposite verb, as viewers will see when a stag “prank” goes horribly wrong, with an eve-of-wedding groom being immured in a coffin. James — who is extremely claustrophobic — decided to visit a Brighton funeral parlour and asked to be sealed into a coffin, to try to discover how long someone could survive. It was, he says, the worst 30 minutes of his life. “The rest of the staff had gone out to attend funerals or collect bodies, and there was just this elderly great granddad there, about 95. I started thinking, what if he drops dead? What if he goes out to get a coffee and gets run over? What if there’s a spider in the coffin?”

He’s done “some dumb things” in the interests of research, he says, including being shot at in Moscow, when he was spending time with a Russian detective. Both escaped unscathed.

Then there was the time he set up a publicity stunt in which he was attempting to surface from Shoreham Harbour at the wheel of a van. The diver meant to rescue him from the van couldn’t get the driver’s door open because of water pressure, so the spectacle had to be faked.

A visit to a police station in Munich gave him ideas for a particularly grisly death. “They had one of these paternoster lifts and I thought they were really scary; I always wondered if someone could get cut in half by one of them.” Instead though he named two of his protagonists Niall and Eden Paternoster. And often in his books he uses the names of real people, generally in exchange for donations to his favourite police charities.

James, whose father was “a disinterested and lapsed Anglican”, more or less assumed his mother was Catholic when he was growing up. That assumption lasted until he went to Charterhouse School at 13 and was confronted by a row of boys shouting “Jew, Jew” at him. “I called my mother the next day and said, are we Jews? And she said, no, darling, we have a little bit of Jewish blood way back in our history”. So the next day James leapt on one of the tormentors and “beat the crap out of him. And it stopped”.In fact, however, Mrs James, born Cornelia Katz, was a Jewish refugee from Vienna who arrived in Britain after Kristallnacht in 1938 “with the clothes she stood up in and a suitcase full of glove leathers, because she had been studying fashion design at the Vienna Art College”. Under the name Cornelia James she became glove maker to the Queen: sharp-eyed readers will often find a mention of a fashionable Cornelia James scarf or pair of gloves being worn by a female protagonist in her son’s books.

In all there were seven Katz siblings, some of whom stayed in Britain and others who went to Canada. His grandparents got out of Austria, too, and went to live in Leeds.

After Charterhouse, James went to film school, where for a brief time he worked as Orson Welles’ house cleaner. But in 1970, he says, there were no jobs to be had in the UK, and so he went to Canada, where one of his mother’s younger brothers had done well as a computer scientist.

“I arrived in Toronto on a Friday night to find a whole beautiful Shabbat meal waiting for me” — along with never-met relatives who did not believe James knew nothing about his Jewish heritage. Their introductions soon led him to prolific work in Hollywood. In all, he has been involved in 26 films as writer and/or producer, including 2005’s Bafta-nominated The Merchant of Venice.

James says he “embraced” being Jewish: but It didn’t please his mother. After his first novel, Possession, was published in 1987, he was the subject of a two-page feature in the Daily Mail in which he attributed his success to his mother’s creativity and Jewish background. A cross Cornelia James phoned him and said: “Why have you told the whole world we are Jewish?”

It wasn’t until 1999, when she lay dying in a Brighton hospice, that Peter James’ mother confessed to him that she had hidden her Jewish identity from him and his sister because she was scared that antisemitism and the Nazis would return and affect them.

With such a family history, it was inevitable that James would write about it — and, indeed, he is doing just that. His latest book is inspired by the mystery surrounding the death of his mother’s sister, his aunt Erica, found at the bottom of Niagara Falls.

One of James’ uncles swore she could have been pushed over by her “ne’er-do-well” husband, though Erica may have succumbed to severe depression suffered after after being raped by a German border guard as the family escaped from Vienna to Switzerland, just before the war. The book — entitled Downfall — also takes in the way Swiss banks held on to the deposits of Holocaust victims. 
 It’s a departure from his stories of life in Brighton for DS Grace His publishers describe him as “writing the everyday sinister.” He says: ”I like that — I like the idea that what I write about could happen to anybody.

Grace, starring John Simm, is on ITV on Sunday March 14. Left You Dead is published in May 2021