I mean it could cost a chapter or in Horrible Histories author Terry Deary's case it might mean the difference of a decade or more in his comic chronicles of the days of yore.

With somewhere around the 50 mark already under his belt as part of a catalogue of 128 books in the UK and 250 more worldwide, it already can't be easy coming up with new ideas. So taking time out for a chat must be a labour of love.

"It's actually nice to give my brain a bit of a rest," he says, inadvertently implying that anything he might be asked is going to be rather less demanding than Rotten Romans, Terrible Tudors, Crafty Cavemen or whatever else the former actor, theatre director and drama teacher might be coming up with next.

The Sunderland-born writing machine reckons he can bang out a book in six days if necessary and always has about 20 on the mental back burner at any one time.

"I'm doing a job I enjoy doing so I'm absolutely thrilled to be paid for it and successful at it," he says from the converted pub in County Durham he calls his home.

Although now universally known as the creator of the Horrible Histories series - two of which are at the Grand Theatre for the rest of this week in a stage version – he had been writing fiction for 15 years before the first one came along.

"I did a Father Christmas joke book which was successful so it was suggested I had a go at a history joke book too," he says. "I was asked to put in a few facts to give it variety and when I started to research them I found I was more interested in that than in the jokes. It wasn't like I woke up one morning with the idea – it just evolved."

He admits that with so many now under his belt – Horrible Histories alone have sold 11 million copies in 29 languages – the series is slowing down but he has now diversified into Shakespeare Stories, Greek Legends and a city series which in turn have evolved into plays which can be performed in the areas they relate to.

"There's a television series planned for next year too and my one man History Roadshow plus plenty of other things in the pipeline," says Terry.

As for the stage version of his Horrible Histories he says he is delighted the way it has worked out.

"I didn't want just a straight dramatic rendition so it was good to be able to go back to my drama roots and see how they would best work," he said.

As for the success of the series itself he reckons his track record as an entertainer has helped.

"I didn't want to produce something that left readers staring out of the window," he says. "I wanted to combine the gruesome with the truthful, the heartwarming and the sad.

"They show humanity at its best – as well as its worst – and how to react.