Bestselling author and Oxford lad John Grisham (Oxford, Mississippi that is) talks about his latest legal novel – for children.

His legal thrillers grace the best-seller shelves of every mainstream bookshop on the planet and are among the most popular choices for travellers.

Indeed, John Grisham, of Oxford...er... Mississippi... once held an impromptu book signing on a 747 after word got around that he was in first class and piles of his novels were passed to the front of the plane by fellow passengers wanting an autograph.

Yet the former Mississippi lawyer remains a largely anonymous figure.

While many of his books have been made into big budget movies, including The Firm, starring Tom Cruise, The Pelican Brief, with Denzel Washingtonand Julia Roberts, and The Client, starring Susan Sarandon, Grisham has never yearned for a glitzy lifestyle in Hollywood.

The 55-year-old, whose legal thrillers have sold in their millions, been translated into 29 languages and published in more than 40 countries, prefers to go quietly about the business of writing, does very few interviews and stays out of the spotlight, living on his 1,000-acre farm in rural Virginia with his wife of 30 years, Renee.

But on his first visit to England in four years he is affable, more casual than the smart-suited ex-lawyer you’d expect.

“We’re bumpkins,” he explains. “I’m just not cut out for city life. And that’s good. I don’t want to be recognised.”

On this visit, he’s keen to talk about his latest novel, Theodore Boone, the first in a new children’s series aimed at eight to 12-year-olds.

The eponymous hero, a 13-year-old legal eagle whose parents are busy lawyers, spends a lot of time in the courthouse and knows all the officials, police and judges.

Theo is drawn into a murder trial when he finds a witness whose evidence could change the verdict. As in all Grisham’s books, there’s a dilemma – the witness doesn’t want to be identified.

Grisham says his move into children’s fiction was mostly to encourage children to read and educate them about the law – but he also had another motive.

“I’m trying to catch Harry Potter, I’ve been after him for 10 years,” he jokes, with mischief in those piercing blue eyes.

“Back in the Nineties I was routinely introduced as the best-selling author in the world and I was trying to act like it was no big deal, then along came Harry Potter and suddenly I became No 2. I really miss being No 1...”

Grisham may have branched out into children’s books but he’s keen to continue with the legal thrillers.

The next one, The Confession, is due out in the autumn.