Children are hiding their packed lunches and sitting alone at break time due to shame about how little they have to eat, a headteacher has said.
Dr Nick Capstick, head of Drove Primary School in Swindon, said teachers were bringing in food to feed pupils who were arriving at school tired and unable to concentrate because they're so hungry.
The Mirror and the National Education Union are campaigning to widen the free school meals scheme to all primary pupils in England.
Speaking at a Feed the Future event in Westminster, Dr Capstick blasted the "pathetic" threshold to qualify for free school meals - and said pupils were failing to mix with their classmates through tiredness and shame at their meagre lunches.
"We are seeing children who are so fatigued that they literally cannot work first thing in the morning," he said.
"Teachers are going to foodbanks, bringing food into school and feeding their kids before they can work because they know there is a direct correlation between feeling hungry and not doing an awful lot because your mind is focused on what you could be doing...which is eating something nourishing."
He added: "Kids are hiding their lunchboxes, they are eating alone with the lid on the lunchbox so no one can see what they're eating, sometimes turning their backs on friends, not talking."
It comes as Rishi Sunak faced calls to offer a lifeline to hard-up families by extending free school meals to hundreds of thousands of needy kids.
Around 1.9 million pupils in England can get free school meals - equating to 22.5% of all pupils, up from 20.8% in 2021 after the pandemic pushed more families into hardship.
But an estimated 800,000 children living in poverty miss out on school meals due to strict eligibility rules.
Chef Tom Kerridge, who grew up receiving free school meals, helped serve lunch to MPs and policy makers at the event - with all guests arbitrarily given either a free lunch ticket or a packed lunch to mimic the system in schools.
Mr Kerridge said it was “upsetting” that the matter was still up for debate and told MPs who oppose the plan: "You need to look at yourself in the mirror as these children are our future."
NEU President Louise Atkinson, who also received free school meals as a child, said pupils were being teased by their classmates over their lunches.
"As a teacher I see in my school, the difference between what children have in their packed lunches, what children have in their dinners," she said.
"If you offer it [free school meals] to all children then they can eat together."
Dr Camilla Kingdon, President of the Royal College of Paediatrics and Child Health, said children’s doctors were having to retrain to deal with the cost of living crisis and poor diet was "front and centre" of their work.
Tory former Health Minister Lord Bethell said free school meals were a "precise, surgical intervention" that catches children at the moment they need it most.
"It removes a whole set of traumas many children have around hunger, around food, around where their food security is going to come from," he said.
Liberal Democrat Education spokesperson Munira Wilson said: "You can't have growth without education and skills... however, children don't learn in a vacuum.
"If they don't have a decent home, if they don't have food in their tummy they can't learn."
