Amount of Raac in English and Welsh prisons won’t be known for at least two months

Scaffolding outside Hornsey School for Girls in north London, which is having to reinforce the ceilings in a number of classrooms. This week a construction expert said Raac was likely to have been used in universities and prisons. Photograph: Leon Neal/Getty Images

The amount of potentially crumbling concrete used in prisons will not be known for at least two months as surveys have yet to be done, the prison officers’ union has said, expressing alarm at the slow timetable.

The prisons service for England and Wales told the Prison Officers Association (POA) that it did not believe reinforced autoclaved aerated concrete (Raac) existed in accommodation buildings, something the union said appeared to be “wishful thinking”.