School cooks and canteen staff are blaming the Naked Chef for a sharp drop in the number of children eating school dinners that could cost them their jobs.

Mr Oliver’s Channel 4 programme, Jamie’s School Dinners, forced ministers to pledge pound;280 million to improve lunches by highlighting the poor quality of meals and the fact that the ingredients in some cost only 37p.

But his war on chips and Turkey Twizzlers has also led to parents turning up their noses at the food offered by schools.

Catering chiefs have accused Mr Oliver of doing more harm than good, persuading children to replace hot dinners with cold sandwiches, and vegetables with crisps.

Neil Porter, chairman of the Local Authority Caterers’ Association, warned that dinner ladies’ jobs could go if children stay away from school canteens. “Media coverage has certainly helped to make the Government move faster, but it has given a poor perception of the service, which is unfair.”

He said a survey by the Food Standards Agency showed school meals were more nutritious than packed lunches.

Gateshead has seen a 20 per cent drop in take-up of primary meals since the TV series, despite winning the National Catering Team of the Year award for the quality of its food.

Dale Robson, head of catering, said: “It is down to Jamie Oliver. The food in Gateshead bears no relation to what you see in his programme. We are doing everything that fits in with healthy eating but now we are going to have to do more to get pupils back on board.”

Elizabeth Luke, South Tyneside catering manager, said: “The programme has had a devastating effect on school cooks. They see these poor packed lunches and yet they are the ones accused of being unskilled, serving up convenience food and contributing to obesity.”

A spokesman for Channel 4 said: “I have to say there aren’t very many councils who serve good meals but I haven’t heard of any saying they serve shit food.”