A Tavistock author who took more than 20 years to complete a book has won a prestigious award.

Philip Reeve, 42, scooped the Chartered Institute of Library and Information Professionals (CILIP) Carnegie Medal, the UK's oldest children's book award, for Here Lies Arthur, an adventure story for teenagers.

"I didn't believe it at first," says Reeve, "but as I got over the shock and it began to sink in, I felt totally honoured.

"It is very special to win the CILIP Carnegie Medal. It has such a history and I admire so many past winners' work it is quite humbling to be ranked alongside them."

Philip Reeve: "It is very special to win the CILIP Carnegie Medal. It has such a history and I admire so many past winners' work it is quite humbling to be ranked alongside them."

Mr Reeve, who was born in Brighton, beat off strong competition from six other authors to land the coveted award, which is now in its 71st year.

Former Conservative politician Michael Portillo presented the prize to Mr Reeve on Thursday afternoon.

"Here Lies Arthur is an outstanding book, and deserving winner," said Tricia Adams, chair of the 12-strong librarian judging panel.

"Reeve's is a consistent story-telling voice that brings us a subtle and credible retelling of the King Arthur myth.

"It is both a page turning adventure story and a clever historical novel. It also has clear political resonance for our times, demonstrating humanity's need to sustain hope and optimism, and our tendency to favour myth over reality to achieve that end."

Previous winners of the CILIP Carnegie Medal include Eleanor Farjeon, Anne Fine, Elizabeth Goudge, CS Lewis, Mary Norton, Noel Streatfeild, Philip Pullman and David Almond.

Mr Reeve already has three major book prizes to his credit. His first novel, Mortal Engines, was an instant success, winning both the 2002 Nestle Smarties Gold Award and the 2003 Blue Peter Book of the Year.

Mortal Engines was the first of his Hungry Cities quartet, the last of which, A Darkling Plain, won the Guardian Children's Fiction Prize in 2006.