The new “Spill The Beans” report invited teenagers aged between 13 and 19 to take part in panel discussions about food in their schools between June and September this year.

It found somes schools were offering 11 different types of dessert, as well as biscuits, doughnuts, pizza, sausage rolls, fried chicken wings and pasties.

Many youngsters said their schools had ditched healthier options such as fruit and salad bowls. Where healthier food was available, it was priced far higher than junk options, the report found.

Many schools struggled to operate kitchens during the pandemic because of food and staff shortages.

‘We need a reset of school dinners’

Nick Capstick, chief executive of the White Horse Federation of 32 schools in southwest England, told the paper: “In the wake of Covid this is a call to arms. We need a reset of school dinners, and if that does not happen, we will have new problems to deal with.”

Oliver says that efforts to tackle the problem are too patchy to make a difference nationally, and that all children deserve the same high standard of school food.

The Bite Back report calls for active monitoring of food in schools and an improvement in the quality of food. It also wants a 400-metre exclusion zone around schools where unhealthy food cannot be sold. Menus should also be published on the school website, the charity says.

The government is currently considering a national food strategy which includes a call to carry out regular inspection of school dinners, and is due to respond next year.

Henry Dimbleby, the Government’s food tsar, has published his national food strategy containing proposals to extend free school meals to more children and to inspect the quality of school dinners.