ROY WILLIAMS compares school timetables to three-dimensional Sudoku puzzles and he should know. An assistant head for 20 years, Mr Williams left teaching five years ago to devote himself entirely to the mysterious art of timetabling.

Although most heads view this as a time-consuming, brain-curdling task they would do anything to avoid, Mr Williams can’t get enough of it. Based in Brentwood, Essex, he tours the country writing timetables for more than 20 secondary schools.

“This is the busiest time of year for me, but it’s also the best,” Mr Williams said. “Timetabling is an intellectual challenge. I love it.

“I enjoy being able to give people the sort of help I never had when I started writing timetables as an assistant head.

“If you know what you’re doing you can solve in three seconds a problem it could take someone else three hours to solve. It’s about lateral thinking.”

Mr Williams charges anything from pound;2,000 to pound;12,000 for the work, depending on the size of the school and the complexity of the timetable.

When not writing timetables he works as a recruitment consultant as well as training groups of assistant heads and data managers in the art of timetable writing.

“The ultimate challenge is going to be the 14-19 curriculum, with schools having to fit their timetables around the courses offered by the colleges,” he said.

Mr Williams is 63 but says he has no plans to retire.

Ian Howard, assistant head of Hackney Free and Parochial secondary in east London, said he could not write the school’s timetable without help from Mr Williams.

“Watching Roy is quite incredible,” said Mr Howard. “You can see he has all the lessons in his head. If there is problem, he can think of a solution. I rely on him totally.

“My predecessor had to take two weeks off during the summer term to get it done, not to mention all the work leading up to it.”

According to Mr Howard, most schools are moving towards having their timetables written by consultants. If they do not, he said, “their assistant or deputy heads will be locked in a room working away for a considerable time”.

Mick Brookes, general secretary of the National Association of Head Teachers, said that it would be worthwhile for schools to employ professional timetablers if it saved two weeks or more of a senior manager’s time.

“If heads and assistant heads are going to focus on teaching and learning, then they need the ability to offload some of the more mundane tasks,” he said.

“What worries me is the uneven playing field. Not all schools will be able to afford this kind of help.”