“I do not want to declare war on chips, but on average our schoolchildren eat chips three times a week and we need to make sure that alternatives are also made attractive so that schoolchildren positively choose to eat well.”

He said he would be “consulting widely” on the standards and how they should be implemented. “This is about social skills as well as healthy choices, and should be seen as part of developing a healthy school policy.”

The previous Conservative Government abolished the minimum nutritional standards shortly after it came to office in 1979. But voluntary guidelines introduced earlier this year were criticised by UNISON for being too lax.

Mr Blunkett said the quality of school dinners had deteriorated over the past 18 years and the number of children eating them had dropped significantly.

Last year, 43 per cent of pupils took school meals compared with 64 per cent in 1979.

An estimated 30 per cent of children did not have a cooked evening meal, he said. “For some, a school dinner is the only real meal a child gets in the day. It needs to be a decent meal, not junk.”

The announcement was welcomed by the Local Authority Caterers’ Association, which recently staged a National School Meals’ Week to highlight the need for a balanced diet, combined with regular exercise.

Arnold Fewell, the association’s press officer, says caterers and educators are working closely together to put healthy options on the menu.

The LACA has also introduced a “Mark of Distinction” prize for at least four schools with successful, healthy-eating initiatives, which will be awarded next spring.

Mr Fewell says there are already positive signs of a shift towards a healthier diet, with pizzas, pasta and jacket potatoes replacing burgers in popularity.