Education Secretary Ruth Kelly announced the plan in a speech aimed at raising the morale of school catering staff, who have felt under attack since TV chef Jamie Oliver exposed the poor quality of many school lunches.

The minister told a Unison conference this week that its members were “the unsung heroes of the education system”.

She announced that the school catering qualification would be available from the autumn and would give dinner ladies proper recognition for their skills.

School catering staff told the conference that they had felt unappreciated since the Channel 4 series Jamie’s School Dinners, which they said gave parents an unfairly poor impression of school meals.

Neil Porter, chairman of the Local Authority Caterers Association, said that uptake of school lunches had fallen by an average of 8 to 9 per cent since the series was broadcast, putting jobs in danger.

“These staff have already been criticised for what they are doing,” he said. “On top of that their jobs are at risk. They are feeling very bruised and demotivated now.”

Dorothy Ratcliffe head cook at Norton college in Malton, north Yorkshire, said: “Our meals are excellent so I was a bit cross with Jamie Oliver. He makes out that we all serve up bad meals, but we don’t.”

But Mrs Ratcliffe said that additional training would be appreciated.

“There are a lot of people who haven’t got a clue - unlike my dinner ladies,” she said.