Teenager Fraser Doherty has landed a major contract with Tesco to sell his home-made preserves in 230 stores.

Doherty, 18, started making jam at home when he was 14 following his grandmother's secret recipe. Until now his parents have helped fill and label jars, which he sold door-to-door in his local area. But now, with sales already at 40,000 jars a month, Doherty plans to recruit staff for the first time.

"Fraser's jams have injected new life into one of the world's oldest foods," said Tesco jam buyer Danielle Peirce.

Super Jam, which is made using superfruits such as cranberries and blueberries, costs £1.43 for a 212g jar.