Eight in 10 primary schoolteachers in England are spending their own money to buy items for pupils who are increasingly arriving at school hungry and without adequate clothing, according to new research.

Almost a third (31%) of those who took part in the survey said they were seeing more hungry children in class, with 40% reporting an increase in pupils coming in without proper uniform or a warm winter coat, research by the National Foundation for Educational Research (NFER) found.

As a result, teachers who may be struggling with their own financial pressures are dipping into their pockets. A quarter of primary schoolteachers said they had spent more than £100 over the past academic year, while almost one in five (19%) said they were specifically buying either clothing or food.

Two-thirds of primary teachers reported spending their own money on classroom materials for art or science, for example, while two in five (42%) had paid for learning resources for pupils including stationary and revision books.

The crisis is slightly less severe in secondary schools, where just under two-thirds (62%) of teachers and senior leaders – compared with 79% in primaries – report spending their own money to buy items for their pupils and schools, with one in five estimated having spent more than £100 this year.

Jude Hillary, NFER’s co-head of UK policy and practice, said: “Teachers are going above and beyond to meet pupils’ pastoral needs using their personal funds. This unrecognised, informal support is being offered at a time when teachers individually continue to face their own financial pressures.”

The report, published on Wednesday, says school finances are deteriorating, with 93% of primary and 87% of secondary leaders forced to make cuts in at least one area due to cost pressures. One area likely to suffer is school buildings, with almost half (46%) of primary leaders and a third of secondary cutting plans for building improvements.

The NFER’s cost-of-living report is based on a survey of almost 1,300 teachers and senior leaders across mainstream primary and secondary schools in England.

Daniel Kebede, the general secretary of the National Education Union (NEU), said: “The fact that children are arriving at school hungry, with unsuitable clothes and having to be supported by teachers out of their own pockets, says everything we need to know about the impact that child poverty and the cost-of-living crisis is having on children and young people.”

A Conservative party spokesperson said: “Under the Conservatives, free school meals have been extended to more groups of children than any other government over the past half-a-century – doubling the number of children receiving free school meals since 2010 from one-sixth to one-third.

“Our plan to set children up for a brighter future is working as we continue to climb up international education rankings and boost school funding to the highest ever level in real terms.”