One in five children arrives at school hungry every day at some schools, politicians have said.
A growing number of children are starting their first and final years of primary school underweight. And too many children have hunger as “their most constant companion”, according to a cross-party parliamentary group on hunger.
In addition, hospital admissions resulting from malnourishment are also increasing, the group’s report said.
Labour MP Frank Field, who chairs the group, said that a breakdown in parenting and a rise in the number of low-income families was behind the trend.
The report looked at 19 schools in Birkenhead and 13 in South Shields, with some staff reporting increased hunger in pupils on Mondays and after school holidays.
Mr Field spoke of how, at a school fun day, "one little mite in Birkenhead", said: "I don't mind missing the activities, but please can I come in and eat? I've had nothing today and I'm starving".
The all-party parliamentary group has called on the UK Statistics Authority to help it confirm the true scale of hunger across Britain.
The average household required 25 per cent of its income to cover the costs of food, fuel and housing at the end of 2014, an increase of 5 per cent since 2003, the report stated.
Mr Field said: "Something very troubling is happening and there are at least two forces operating. One is the breakdown in parenting, and the second is an increase in the numbers on a low income.
“It's a tragedy if one of these strikes a child, but it's an unbounded horror if a child is hit by both. How can the world's fifth richest nation not know the extent of physical damage caused to its own children by a lack of food?
"Too many people in Britain are hungry. How many? We do not know. A very large part of this group of hungry people are children… Too many children have hunger as their most constant companion."
Christine Blower, general secretary of the National Union of Teachers, has called on the government to recognise the damage that low wages have on the population.
“It is shocking that children in modern-day Britain have to cope with malnutrition and hunger as part of their everyday experience," she said. "Teachers know only too well the impact that poverty has on pupil’s learning and general wellbeing. No-one can learn and play effectively when they are feeling miserable and tired through hunger."