Lee Child's approach to writing a bestseller can seem strangely workmanlike.

While other authors agonise for days over a sentence, their craft appearing more a burden than a pleasure, when Child turned to writing in the mid 1990s he had a much more pressing inspiration – the need to pay the bills.

After a successful career at Granada Television, the company's golden age which had produced the likes of Brideshead Revisited, Prime Suspect and Cracker, came to an end and Child found himself among the casualties. Without a regular income, he decided to write a book. While most first-time novelists hope that one day their efforts may allow them to give up the day job, Child, who had just celebrated his 40th birthday, couldn't afford his book to be anything but a success.

An avid reader of crime fiction, he already had a rough idea for a plot and like any good salesman decided to target the largest possible audience. While Ian Rankin's Inspector Rebus never wanders too far from Edinburgh's city boundaries, Child has been honest enough to admit that his Jack Reacher novels are set in America because the country provided a bigger market.

He was right. His latest novel Nothing to Lose was the most pre-ordered book ever on Amazon and his 12 previous books have been published in 29 million languages and sold 15 million copies.

"What people buy is completely unpredictable," says Child, who studied law at the University of Sheffield, before moving across the Pennines and joining Granada. "However, one thing I learned during my 18 years in television was you go where the audience is. America seemed like a good place to start. The idea for a crime novel had been rumbling around for a few years before, but when I found myself out of work it was necessity that made me sit down to write.

"When I talk about wanting to sell as many books as possible people sometimes assume that it means I'm somehow wholly driven by money. That's not the case at all, but there's no point making a film no-one wants to watch or painting a picture no-one can see. The amount of books you sell is the only way of judging how effectively you are communicating with readers and I make no apologies for that."

Worried perhaps that his success could disappear as quickly as it came, Child is no less disciplined when it comes to output. Since 1995 he has published one Jack Reacher novel a year and there is little sign his creativity is about to dry up.

"I don't want people to have the opportunity to forget who I am," he says. "I suppose I do have a very structured approach to writing, but for me it's important to know that each year there will be a new book.

"When I'm in the middle of a novel I sometimes worry that there's nothing left to write about, that I'll never be able to come up with a new plot, but usually by the end the idea for the next book is already taking shape."

One thing which has set Child apart from the glut of crime writers is his central character. At 6ft 5in tall and sporting a 50in chest, Jack Reacher is a nomadic alpha male who seems to have been born with more than his fair share of testosterone. However, unlike the tried and tested detective blueprint he doesn't have a drink problem, a terrible home life or the tendency towards emotional breakdown.

"It seemed to me that formula had been done to death," he says. "I wanted to write about someone noble."

With Tom Cruise's production company having bought the rights to his ninth novel One Shot it seems only a matter of time before Child and Reacher make it to the big screen. The deal was reported to be worth $20m, but after his years in television, Child knows better than to get excited by industry backslapping

"Hollywood works in mysterious ways," he says. "The rights to so many books are bought, but only a few ever get commissioned. The only way a film gets made is when the money man, the director and the star all happen to get together and agree the project is a goer. It seems to me to be an entirely random process, so I'm not getting my hopes up.

"If it ever did make it into production I would much prefer if they cast some unknown to play Jack rather than some big star. I'm not sure it can work that way any more, but I would love it if a film could have the same effect for a young actor that James Bond had for Sean Connery."

Child now lives in New York with his American wife, but he comes back to England fairly regularly and already has a date in his diary for November. Having accepted a visiting professorship from the University of Sheffield he will return to Yorkshire to run a series of workshops and for the inevitable trip down memory lane.

"I want to show the students that everyone can succeed eventually," he says. "I had to repeat a year of my law degree when I failed the end-of-year exams and it took me a bit of time to get where I am today, but once I had found my niche, something I am passionate about, everything else just seemed to fall into place.

"When I was at university the curriculums particularly for something like English literature were incredibly formal. It's great to see they have shaken things up a bit and I'm looking forward to revisiting some of my old haunts. I have relatives in the city and whenever I visit I always feel at home."

Despite the seemingly effortless career and being the toast of the New York literary world, Child admits that an author's life can be a lonely one. "But it's a great job and sometimes I do have to pinch myself that it's worked out so well."