My grandson is just two and a half. As I watch him inventing games, delighting in the books I read him or hungrily absorbing the world around him, I marvel at how quickly the characters of young children are formed. It’s one of the joys of primary teaching, of course: all those little people, all so different and all so interesting. Looking back over my headship awakens memories of many fascinating children. Like eight-year-old Frankie.

Frankie wasn’t a challenging child; he had no medical problems and he was never absent from school. But he did have an all-consuming passion for buses. He had joined us from another school and it was a fortnight before I met him properly. I was chatting to his teacher as she supervised playtime when he wandered up to us. “Shall I do a bus, Miss?” he asked.

Seeing my baffled expression, his teacher smiled. “Frankie’s my very own bus service,” she said. “Shut your eyes and listen.”

Frankie launched into an impression of a bus in motion, with gear changes, stops and starts, and hissing air brakes. It sounded just like the real thing. “What bus was that?” he asked.

“I reckon it’s a 53,” his teacher said.

“Of course not!” Frankie replied indignantly. “It’s a bendy bus. This is a 53.” He did a second impression, which sounded very different.

Each day, as I chatted to the children as they came in after break, Frankie would hurry past making motoring noises. I discovered that he had drawn elaborate maps of the school, recreating the building as a large chunk of south-east London. Bus routes were illustrated with coloured lines and stops were marked at intervals. To catch the P13 to Streatham, also known as the dinner hall, you had to wait outside Class 9, where buses should appear at 10-minute intervals if they were on schedule.

Frankie could give any activity a transport slant. On an outing, while other boys compared the contents of their lunch boxes, Frankie unfolded a huge bus map, laid it out on an empty seat and carefully studied the route the coach was taking. I was relieved he wasn’t sitting behind the driver, because I could imagine him pointing out that he wasn’t taking the most expedient route.

His South African class teacher was initially unfamiliar with London, but after teaching Frankie for a year she felt she could travel anywhere by bus. Frankie simply loved them. He drew pictures of them whenever he had access to a pad of paper and some coloured pencils, he spent a lot of time in the London Transport Museum and he built models of buses with empty cereal packets that his grandparents gave him to bring to school. We were certain that he would eventually find a career working with them and I would love to know if he did.

Soon after Frankie left us for secondary school, I met him one Saturday morning in a store miles from where he lived. He was shopping with his mother. “Wow, you’re a long way from home,” I said. “How did you get here?”

“Oh God, please don’t ask him that!” his mother said. “We’ll be here all morning!”

Mike Kent is a retired primary school headteacher. Email: mikejkent@aol.com