Kent food producers are urging consumers to buy locally-grown food as new research shows some supermarket and shop prices have risen by more than 40 per cent since January.

The new BBC Food Price Index, designed to track the cost of a typical trolley of food items, found seven products surveyed were found to have gone up in price by more than 40%.

These included a pack of four croissants, now 47.4 per cent more expensive and a 125g packet of ham, which went up by 45.4 per cent. The price of a medium-sized chicken increased by 41.9 per cent.

The survey, compiled by Verdict found meat and fish was up 22.9 per cent, while fresh fruit and vegetables rose 14.7 per cent. The general price rise for all types of food was 8.3 per cent.

Farmer Alastair Jessel, who runs two farm shops - Taywell Farm Shop, Goudhurst and Taywell at the Vineyard, Lamberhurst - believes that against the background of rising fuel costs, buying fruit and vegetables is now significantly cheaper at the farm.

He said: "People need to remember that getting in a car and driving to a supermarket costs a lot and also people falsely assume that supermarkets are the cheapest.

"If they were to look carefully they would find a lot of items cheaper in local farm shops than in a supermarket."

There are more than 60 farm shops in Kent.