Hungry schoolchildren are stealing toast and sharing individual packed lunches because they cannot afford to eat, research reveals.
Many are still turning up to school hungry and skipping meals at lunchtime, according to a report by the Children's Society charity.
The study, based on a survey of around 570 teachers, reveals serious concerns among school staff about the levels of hunger among pupils.
Almost three in four (72%) of the teachers surveyed said they have seen pupils coming into school with no lunch and no way to pay for one.
The study, conducted with the Association of Teachers and Lecturers (ATL) and the National Union of Teachers (NUT), also reveals that two-thirds (66%) of school staff say that teachers are providing pupils with food or money for meals if they turn up for lessons hungry.
One teacher told researchers: "They come to school and have not had breakfast. They take toast that they have not paid for because they are so hungry."
Another said that they see a "significant" number of pupils who do not have a mid-day meal because they have no money.
A third teacher reported: "Last month I found two girls sat on the toilet floor sharing one's packed lunch because the other girl had no lunch money."
There were also concerns raised about the size of school lunches, with one teacher working at a school in a deprived area saying that pupils are often given not much more than a teaspoon of rice or cous cous and only one or two cubes of meat.
While more than half (58%) said that lunches were an adequate size, around a third said that they were quite small or inadequate.
Earlier this year, ATL raised concerns about portion sizes, suggesting that young children are being served "very small" school dinners and given limited choice despite paying more for their meals.
According to The Children's Society's figures, more than half of the 2.2 million children living in poverty in England miss out on a free school meal each day.
Of these, around 700,000 are not entitled to one, and a further 500,000 do not take them up because of barriers such as fear of bullying or being stigmatised, the charity said.
Matthew Reed, chief executive of The Children's Society, said: "This report sets out shocking evidence of just how much hardship teachers up and down the country are witnessing in classrooms day in, day out. Something is going badly wrong when teachers themselves are having to feed children.
"Every child in poverty should be given a free school meal. Free school meals are key to moving children out of poverty and vital to helping them flourish."
ATL president Hank Roberts said: "It is deeply worrying that our teachers are seeing pupils arriving at school unable to pay for their lunch and are too often going without."