The Key, a national education support service, questioned 667 heads and school business managers on the state of their buildings. 38 complained of overcrowding, whilst another 25 warned that their environment was a health and safety hazard. Overall, 49 per cent of secondaries and 33 per cent of primaries were classed as "unfit for purpose" by respondents, the Observer reports.

"Many schools are in a worse condition than they were ten years ago. Some are in a terrible and dangerous condition," Nusrat Faizullah, Chief Executive of the British Council for School Environments, said. "Headteachers and local authorities had to prioritise where to direct resources for maintenance and repair, influenced in part by the promise of more money for school buildings under the previous Government's school building programmes. This meant some schools had urgent repair needs postponed because of an expectation that significant money for buildings was on the way, only for it to be cancelled.”

Confusion over the choices for refurbishment, a baby boom and delays to Government decisions have been cited by headteachers as reasons why many school environments are in such poor condition.

After scrapping the Building Schools for the Future scheme in 2010, the Education Secretary, Michael Gove introduced the Priority School Building Programme, a £2bn initiative to rebuild the most dilapidated schools in England. At least 476 schools have applied for funding this way, with between 100 and 300 likely to receive money.

A Spokeswoman from the Department for Education (DfE) said schools would hear shortly whether they would receive funds. “We are taking our time to get this right and will announce our decisions as soon as we can,” she said.

In 2010, Teacher Support Network and the British Council for School Environments (BCSE) with the Association of Teachers and Lecturers (ATL) revealed that teachers felt that their school building was not supporting their "ability to teach effectively by providing an environment that has a positive influence on behaviour".

As well as having an effect on behaviour, teachers' criticisms also included lack of space for students to "relax" and an absence of "exciting, flexible and appropriately sized classrooms for students". One teacher said "we currently have 250 more students in our school than we were designed to accommodate". There was also significant concern for "good quality toilets" causing one teacher to comment "students are very vocal about inadequate toilet facilities, which makes them feel unrespected".