“Miss,” Frankie whispers, “I can make bus noises.” It’s the first day with my new class and Frankie is one of my pupils.

This might be normal behaviour in the role-play area of a reception classroom, but Frankie is 10 years old. He points his mouth in my direction and launches into an impression of a bus in motion, complete with gear changes and airbrakes. “Hmmmmmm... psssh... hmmm... hmmmmmm.”

“What bus was that?” he asks as soon as the performance has finished. He expects me to know. I don’t, of course. “The 53?” I say off the top of my head. “453!” he pronounces indignantly. “It’s a bendy bus. This is a 53,” he says, as he embarks on the next imitation. The 53 and the 453 do indeed sound different.

By half term, I’m adapting to his quirkiness. As we climb the stairs after playtime one morning, he plays conductor, announcing our location. “We’re in East Dulwich now. Down that corridor is Peckham Rye. If we go up another flight of stairs we’ll be in Forest Hill.” I understand, because Frankie has drawn elaborate maps of the school, and recreated them as south-east London. The bus routes are marked with coloured lines and there are bus stops at regular intervals. To catch the P13 to Streatham, aka the dinner hall, you have to wait outside Miss Sheppard’s classroom. These maps are regularly updated and copies are handed to me and the headteacher, to keep us abreast of developments.

Frankie has a transport slant on any school activity. On an outing, while other boys concern themselves with the contents of their packed lunches, Frankie will have a bus map unfolded on his lap, following our route.

In the two years I taught him I learned all I’ll ever know about London’s buses. He loved them, studied them incessantly and will undoubtedly find a career with them.

Soon after he’d left us, I met him with his mother in a shop, miles from where he lived. “You’re a long way from home,” I said. “How did you get here?” “Dear God, don’t ask him that,” his mother said. “We’ll be here all morning.”

Nerine Meyer teaches Year 6 at Comber Grove primary school, London borough of Southwark. Do you have special memories of unforgettable pupils? Write to Sarah Bayliss at the address on page 3 or email sarah. bayliss@tes.co.uk