The celebrity chef was shadowed by a BBC film crew that was working on his new series, Raymond Blanc - Kitchen Secrets, to be launched before Christmas. British Tomato Growers' Association (TGA) representative Gerry Hayman said: "We were delighted that Raymond Blanc could take part and were interested to see if his opinions matched those of our regular team of experienced judges.
"As you would expect, he is exceptionally demanding in terms of the food ingredients he uses, but his assessment of the winners matched those of our other judges exactly."
A baby plum grown by Andy Roe of Flavourfresh Salads was chosen as the overall winner of the competition, held last month at the show in Detling, near Maidstone, Kent.
Cherry tomato Piccolo and its "baby brother" Piccolini took five of the remaining top six places. Roe's entry marked a win for the second year running in the competition and saw the grower win prize money from sponsor Marks & Spencer.
Roe also received the David Stapley trophy - which is awarded by the TGA in memory of the celebrated tomato grower from Kent.
More than 30 entries in four separate classes entered the competition - with varieties ranging from tiny cherries to beefsteaks.