He left the dusty lecture halls to lead a more fulfilling life as a teacher, but the world of academe did not forget “part time” historian Stephen Lee, who has been awarded one of the UK’s most prestigious book prizes.

Dr Lee spent eight years of school holidays perfecting his study of George Canning, the early 19th-century prime minister. The effort has earned him the Royal Historical Society’s Whitfield Prize - normally reserved for high-profile university academics.

Unfortunately, his specialist topic is not on the curriculum at Torquay Boys’ Grammar School, where he works. However, Dr Lee says giving up lecturing eight years ago was the best decision he ever made.

He hopes his success will inspire students to go on to university and that it will prove to them that academics are not “strange”.

The Whitfield Prize is awarded annually for the best book in any field of British history. Dr Lee, an assistant head, will share the honour with Professor Frank Trentmann, of Birkbeck, University of London.

Dr Lee, 46, who lives in Teignmouth, teaches for 25 hours a week as well as having responsibility for curriculum at Torquay Boys’. He went back to university as a mature student and received his PhD from Manchester University at the age of 38. He also spent a year as a university lecturer.

The judges said his book was “learned, lucid, beautifully written and penetrating”.

“The pupils just find it intriguing that I’m a historian and I think it interests them a bit,” said Dr Lee. “I hope this will show them there are no barriers and that academics aren’t strange people. It’s important for teachers to carry on learning themselves, and those who are obsessed by their subject seem to be more passionate.”

‘George Canning and Liberal Toryism, 1801-1827’ is published by the Royal Historical Society and Boydell Press.