AN eight-year-old British prodigy astonished the chess world yesterday by becoming the youngest person to beat a grandmaster. David Howell, from Seaford, East Sussex, defeated Dr. John Nunn, one of the world's leading authorities and a former British champion, during an official chess tournament at the Mind Sports Olympiad, at Olympia in West London. Dr. Nunn resigned after being forced into a hopeless position by the child in their ten-minute match. He shook hands with David, then turned on his heel and abruptly left the room. David, the British under-nine and under-10 chess champion, beat the record held by Murugan Thiruchelvan, 10, who defeated the English grandmaster Jon Levitt earlier this year. The youngest grandmaster was the Ukrainian Ruslan Ponomariov, who achieved the feat aged 13 two years ago. Yesterday's competition was a Swiss tournament, a blitz game in which players have only five minutes throughout the match to work out all their moves. David's father, Martin Howell, 48, taught his son the basics of chess three years ago after buying a chessboard for him at a jumble sale. Within two hours the boy was winning. After his victory David said: "Dr. Nunn just walked off after shaking hands. He didn't say anything. I thought he was quite cross because my grade is more than 100 points behind him.