We used to describe our intake as truly comprehensive at the school in a former mining village in Yorkshire where I taught Hayley. It ranged from those who would go to Oxbridge to those who would end up in Armley, the local prison.

Hayley was an enthusiastic member of our field trips. She and her mates liked hands-on geography, and immersed themselves in the subject, quite literally during a stream study in the Peak District. Hayley, Emma and Sarah were made to stand in a field with their hands on their heads as punishment. But Hayley’s results were exceptional, and she went on to get a grade A at GCSE.

When she was in key stage 4, the department did some unusual work in the school grounds. We built our own micro river system and powered it with renewable energy from a wind turbine and solar panels. Later, we decided to replicate the project in a village in Lesotho with which we had set up links. By this time Hayley had left the school and gone on to do A-levels.

After completing a mountain of risk assessments, I led an expedition to Lesotho which brought wind-powered electricity to this remote community for the first time. In January last year I flew out again to plan our next expedition for this summer. As we set off on the return journey from Johannesburg, the plane was just levelling off when who should appear in front of me but Hayley, robed in Virgin Atlantic’s best with make-up to match and bearing a tray with drinks and snacks. “Oh, it’s Mr Dunn!” she beamed.

We were deep in conversation when her supervisor approached and asked if everything was OK. “It’s my geography teacher,” said Hayley to which her supervisor replied “What’s wrong?Has she not handed in her homework?”

Hayley was fascinated to hear of our work in Lesotho and promised to write to Sir Richard Branson to see if he could help in any way. I always thought Hayley was a high-flier. Now, with a bag full of GCSEs, three good A-levels and a thirst for seeing the world, she’s proving it.

Ken Dunn is school development manager at the City School Sheffield. To find out more about the Lesotho project email: admin@city.sheffield.sch.uk.

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