But whatever Jack Sheffield's formula, it's clearly a recipe for success, with his first book Teacher, Teacher! selling over 50,000 copies.

Now the teacher-turned-writer from Gipton is ready to see his fanbase grow still further with the follow-up Mister Teacher, now out in paperback.

"I think people enjoy the fact that they are feelgood books, which is exactly what I intended," says Jack, who was born Jack Linley in Leeds in 1945.

"I wrote the first one for the baby boomers like me who were young professionals at that time and also for all the thousands of primary school teachers out there.

"But I've had lots of emails from 30-somethings who were at school then and can remember the assemblies, the hymn practice and playing on a triangle."

The books follow teacher Jack Sheffield, the headmaster of Ragley-on-the-Forest Church of England Primary School, based on the North Yorkshire village school where Jack himself was headmaster.

Starting in the late 1970s, they see Jack deal with everything from nits outbreaks to cycling proficiency tests and a burgeoning romance with deputy headmistress Beth Henderson.

Diaries

Jack the author says the events in the books are largely the fruits of his imagination, though some elements were inspired by the diaries he kept while he was a schoolteacher.

Jack studied to be a teacher in York and during the summers took a job driving a Corona pop van delivering to homes across Leeds.

One of his favourite photos is of him standing beaming in front of his van in Gipton the day England won the World Cup in July 1966.

"It was a great job and a lot of children were very excited to see me. I really do think it helped make me a more rounded teacher because I met people from all walks of life.

"It helped me grow up a bit and was great preparation for what lay ahead."

After qualifying, Jack taught at various schools in Yorkshire before becoming senior lecturer in primary education at Bretton Hall near Wakefield.

"I loved teaching because it felt like I was doing something worthwhile with my life. The children were wonderful and I think that comes across in the books.

"My pupils still make contact and tell me they remember the times when we went camping or built the school pond. We turned out literate, numerate young people and that makes me feel proud."

But Jack may never have become a teacher if it had not been for a chance encounter with a TV and radio legend.

"Jimmy Savile gave me a lift when I was hitchhiking late one night in 1964," he recalls. "We got chatting and he asked me what I was going to do with my life.

"I told him I was either going to be a policeman, a teacher or join the army. He said he thought I would make a great teacher and I should get myself down to the Corn Exchange the next day because they were holding a a recruitment fair.

"I loved teaching and feel very fortunate that I ended up picking the right profession.