When Tim Williams applied to teach business studies at Tre-Gib comprehensive in Llandeilo, the governors told him they wanted someone to set up Young Enterprise at the 950-pupil Welsh comprehensive. “We want young people here to realise they don’t have to move away from Wales to find work; that if they’re enterprising, work will come to them,” they said.

That was in 2000. And what the governors wanted has begun to happen. For three years in a row, Tre-Gib sixth-formers have been finalists in the UK-wide Young Enterprise awards. This year they won it for the second time.

Their interactive, multilingual CD-Rom on the life and works of Dylan Thomas was, the judges said, “outstandingly original”. And they had the endorsement of the boss of British Airways: a promise from Rod Eddington to advertise their product on the airline’s New York to London flights.

Hardly surprising, then, that Tim - only in his fifth year of teaching - should win this year’s secondary teacher of the year award in Wales. As his pupils said, he’s a special teacher. At every level, his students pick up prizes. He’s a hugely powerful influence.

Perhaps it’s because he came late to teaching. From the age of 16 he worked in banking, but he wanted a degree and, at 27, secured a place at the Swansea Institute. He got a first in business education, taught for an enjoyable year in Slough and jumped at the chance to go back to Wales and “a dream job”.

So who comes up with the ideas? “They do.” He cites the example of the Year 12 project that won this year’s Careers Wales Enterprise competition. ”‘We have cows standing about in fields’, a student said. ‘Why don’t we put jackets on them and sell the advertising?’ So they did. We called them moo-ving billboards. We had companies queuing up - and it made good television news.”

Tim, now an assistant head, says about teaching: “There’s nothing to match that thrill you get when you know someone has learned something from you.”

The final of the Teaching Awards will be held in London on October 24 and will be broadcast on BBC2 in November. Nominations for next year’s awards are open at www.teaching awards.com