Detective Roy Grace creator Peter James on his career ahead of Theakston Old Peculier Crime Writing Festival

“I have such admiration for the police, I’ve been out with them many times and I’ve been scared as hell sometimes – it’s easier to be a keyboard warrior.”

Although he ended up being an award-winning crime writer – having written 20 Detective Roy Grace novels – James started out in the film industry.

“I’d always wanted to write – from the age of seven I kept all my worldly thoughts in a notebook. I had one teacher at school (James attended Charterhouse) who encouraged me, but I had no confidence. For my 17th birthday my dad gave me a portable electric typewriter and I had touch typing lessons from this battle axe of a teacher – if I hit the wrong keys she’d literally hit my knuckles with a ruler – I learnt to touch type out of sheer terror.”

When he was about 18 he wrote what he thought was ‘the great British novel’.

“Luckily it never got published.” Two more attempts also failed so he decided to go to film and television school.

"When I came out in 1970 it was really hard to get a job – there were only two television stations in England.” An uncle who lived in Canada invited him to stay with him in Toronto and he got a job on a daily TV programme for preschool children. “I was the lowest life form on the set,” he recalls. But after about three months one of the writers fell in and he was asked to write that day’s show. “I was 22 and I ended up writing it three days a week for the next year. That was my first real break.”

He moved into the film industry in Canada being involved in the creation of 26 films. "I then made a completely disastrous film which I wrote and produced called Spanish Fly which starred Terry Thomas and Lesley Philips – Barry Norman called it the least funny British funny film ever made. I actually met him in 2014 at the Harrogate Crime Writing Festival as his wife was a crime writer. I bumped into him in the bar and said ‘you b*****d you trashed my film’. He said ‘Sorry but it was a bit s**t wasn’t it ?”

James had put all his money into the film and ended up “skint” as a result.

"I was 27 and I’d had this meteoric rise and fall in the movie business, I hadn’t had a book published and so I returned home and went into the family glove making business and hated it. I’d gone from making movies to inspecting rolls of cloth.”

He then met his wife (now ex-wife) Georgina Wilkin who asked him when he was going to write the novel he’d been talking about. “I read an article about writing a spy thriller and I thought I can do that and so I knocked one out and sent it to my agent in New York. I didn’t hear back.”

It transpired the agent had died five years earlier. James got a new agent in England who managed to get him a two book publishing deal.

"The best day of my life was when the book was accepted for publication the worst day was when it came out,” he says. “I rushed into all the book shops and couldn’t find it anywhere. It turned out they’d printed 1,800 copies and 1,500 of them had gone straight into libraries.” The second book sold even less. Then a friend advised him to stop writing about spies, and write about something he was passionate about and that he could access and research.

"A week later we got burgled and a young detective came to take fingerprints. He saw my books and said if I ever wanted to research the police then give him a call. He was married to a detective, my wife was a lawyer and we became friends.

"One day they invited us to a barbecue with some of their friends – all police officers right across the spectrum. I remember thinking these people see more of human life than anybody. They have this privileged access and they can go anywhere. When they realised I was genuinely interested in what they did they invited me to spend a day with them to see what they really did.”

Over the next ten years James started going out with the police more and more, they’d even smuggle him to crime scenes. “They trusted me, I think they saw me as part of the family.”

In 1997 he was introduced to a young homicide detective called David Gaylor.

“He’d just been tasked with reopening all the unsolved murders in the county of Sussex where there was still somebody alive who could benefit from the investigation, he said he was the families’ last chance of closure and the victims’ last chance of justice – I loved that really human image.”

Gaylor was to become James’s inspiration for Detective Roy Grace, the protagonist in 20 of his crime thrillers and the character played by John Simm in the ITV adaptation of his books. "We just clicked he started to advised me on some of the police aspects of my books.”

In 2002 Gaylor was promoted to head of major crime for Sussex at the same time Pan Macmillan asked James whether he was interested in creating a new fictional detective.

"I went to Dave Gaylor and asked him if he’d like to become a fictional cop and he loved the idea and since then we have worked together on every Roy Grace novel.” The pair have gone on to become best friends, Gaylor was best man at James’s second marriage. "I don’t think the series would have been as successful if I didn’t have that amazing relationship with Dave which continues today.”

He says he had no idea that Grace would prove so popular and initially he just had a two book deal. It was a visit to the Missing Person’s Helpline just a few months before that gave James the idea for the sub plot that would keep readers hooked.

“I thought wouldn’t it be fun to create a detective who has a personal puzzle of his own he cannot solve. I was staggered to learn that 200,000 people a year are reported missing, if they haven’t turned up in 30 days then they aren’t likely to turn up again.

"The people they leave behind are stuck in a limbo because they can’t move on in their lives. The first time we meet Roy we learn that nine years ago on his 30th birthday he came home and Sandy his wife had disappeared and he has been looking for her for ever since and he just can’t move on in his own life. I thought I’d set the mystery up in the first book Dead Simple and solve it in the second book.”

But when Dead Simple came out he was inundated with emails from readers speculating what had happened to Sandy, so he decided to keep the mystery going which he did for the next 14 books. A new book They Thought I was Dead has just been published which tells Sandy’s story.

“It gives people a big surprise,” says James. “ A lot people think they know what happened and it is totally going to surprise them.”

His unique relationship with the police continues, quite often they approach him to highlight a particular issue such as internet romance scams or the crimes that have spring up around demand for certain breeds of dogs highlighted in his latest Roy Grace novel Stop Them Dead which he is talking about at The Theakston Old Peculier Crime Writing Festival in Harrogate next month.

"It’s an event I have always loved, to me it’s probably the first dedicated crime fiction festival in the UK – it’s the one that set the gold standard.”

Theakston Old Peculier Crime Writing Festival takes place in Harrogate, 18-21 Julyharrogateinternationalfestivals.com