Terry Deary has been doing this for 16 years, so is understandably weary of talking about his hugely successful children’s book series.

But with the Horrible Histories train gathering steam, he’s in it for the long run, like it or not.

It all began when Terry’s publishers commissioned him to write some history joke books in 1992 and suggested throwing in a few curious facts. The facts proved more interesting than the jokes so a very different type of book emerged.

But Terry, 63, maintains that even though he found history boring at school, he was never on a mission to rescue it. “My aim with all of my books is to explore the question, ‘Why do people behave the way they do?’ “History looks at why they behaved the way they did, which is a valid vehicle for education. I don’t want to rescue school history – I want that sort of fact-based learning to die, not be ‘rescued’.”

So why did he find history so boring? “The teachers just went through the motions, dictating the same notes they’d used for 40 years,” he says. But Horrible Histories has changed all that.

So what’s the secret? “They balance education and entertainment. Everyone wants to learn – no one wants it to be a chore. Horrible Histories meets that human need,” Terry explains.

But even Terry had no idea his books would prove so popular. “I didn’t expect the longevity. The early readers are now at university and the newer readers weren’t even born. No other children’s series survives, continuously, from the early 90s. Very odd.”

With more than 200 books under his belt, Terry is as prolific as he is successful, so when will he run out of steam? “People write to me from around the world asking for a book on their country or their interest. Life is too short to meet all the demands.

“What I will run out of is motivation. Because each subject area requires a different specialist so there are many researchers. I don’t usually ask where they get their facts and don’t care. My only job is to re-tell the narratives using my skills as a children’s fiction author,” he says.

Luckily, when it comes to the stage and TV, he doesn’t have to. “After many years of looking for a way to adapt the books, the BBC decided they wanted a sketch-show format that would change the face of children’s factual entertainment forever. They hired the best adult sketch writers and comedy actors. It seems to have worked because the show is No. 1 in the children’s viewing charts,” he says.

And with the crowds flocking to anything with a Horrible Histories tag, the theatres are laughing all the way to the bank.

Terry, a former actor, theatre-director and museum manager who lives in the North East, has a favourite Oxford memory. “At a book signing a very posh history student enthused, ‘Your books have inspired generations of children!’ ‘Generations!’ I objected. ‘I’m not that bleedin’ old!’.”

Frightful First World War & Woeful Second World War will be at the New Theatre from June 30-July 4. Box office on 0844 8471588.