Six years ago, the canteen at Hackney’s Mandeville Primary School was a sea of lunch boxes filled with brightly coloured packaged chocolate, crisps and fizzy drinks. Today pupils are tucking into a well-balanced meal of chicken teriyaki, cabbage, rice and coleslaw that costs their families nothing.

Mandeville, in east London, is one of 300 UK schools to implement a programme run by charity Chefs in Schools, which trains cooks to prepare more nutritious food. Doing so can have a positive impact on educational attainment, mental and physical health and productivity, evidence shows.

“They just have more energy,” deputy headteacher Kaltum Yusuf says as children queue up in the canteen, where the menu is displayed on a blackboard, and colourful posters about food and nutrition cover the walls. “A lot of them used to never have fruit and vegetables,” she adds, explaining that many of them were eating mainly junk food at home.