The number of children who are going hungry at home has reached "heartbreaking" levels, the main teaching union has warned.
Four out of five teachers reported a rise in "holiday hunger" among children on free lunches whose families struggle to afford to feed them three meals a day through the holidays, a survey by the National Union of Teachers (NUT) found.
More than one-third (37%) said they saw pupils returning after the school holidays showing signs of being malnourished after starving for extended periods.
A total of 78% also reported children were arriving at class hungry, the union said.
Kevin Courtney, NUT general secretary, said the findings should be a source of shame in modern Britain.
Almost seven in ten teachers (69%) said that pupils' social well-being was negatively affected by holiday hunger, while more than half (57%) of the 600 surveyed said their physical health was impacted.
Mr Courtney called on the Government to take "urgent action" to tackle the problem including extra support for families to tackle holiday hunger.
Around 30% of children are estimated to be on free school meals, considered a key indicator of poverty.