LONDON: More than 150 British schools have been told to close some buildings after they were deemed unsafe, drawing anger from parents and teachers on the eve of a new term and posing a fresh headache for the government.

Britain's Department for Education said 156 schools had been affected by the presence of Reinforced Autoclaved Aerated Concrete (RAAC) in their buildings which authorities have now decided is at risk of collapse.

Britain's education system, still recovering from the home-learning impact of the pandemic, has been hit by six months of teachers strikes in 2023, on top of the challenge posed by what schools say is a lack of funding in an inflationary environment.

The impression that vital national infrastructure is crumbling adds to the challenge faced by Prime Minister Rishi Sunak as he heads for a national election expected next year, following industrial action across education, healthcare and transport.

Education minister Gillian Keegan said the majority of schools affected would remain open for face-to-face learning for all pupils because the problematic concrete was only found in a small part of the school buildings.

But some schools will face complete if temporary closure.

"In some cases, it will be the whole school," schools minister Nick Gibb told Sky News on Friday.

Gibb also said that it could be safe for pupils to work in a classroom with the ceiling propped up by steel girders.

The news that schools will be affected comes just days before most children are due to return to education for the new year after a six-week summer holiday, raising questions over why the government had announced the move at the last minute.

"The DfE and government have squandered valuable months hiding this crisis when they should have been fixing dangerous school buildings," said Mike Short, head of education at trade union UNISON.

Keegan said safety was the government's top priority.

"This decision has been made with an abundance of caution," she said in a statement.