It was a few short lines in the Tory manifesto: an end to universal free school lunches for the first three years of primary school. But to TV chef Jamie Oliver those lunches represent a decade of campaigning for healthier kids.

The battle lines are drawn. The Conservatives say they will provide free universal breakfasts for a tenth of the price of the lunches, saving £600m that could be spent on teaching.

Jamie Oliver has a personal interest: his Channel 4 series, Jamie’s School Dinners, led to a government commitment to improve school meals, and he’s advised four governments on the issue.