A court building has been closed following the discovery of dangerous concrete that could cause it to collapse.

Harrow Crown Court in north-west London has shut after reinforced autoclaved aerated concrete (RAAC) was found during improvement works, the Ministry of Justice told the BBC.

RAAC, lighter and less durable than traditional concrete, was used until the mid-1990s but the Health and Safety Executive said it is now beyond its lifespan and may collapse with little or no notice.

A Ministry of Justice spokesperson told the BBC the closure was temporary and cases would "be heard at alternative sites to minimise disruption while we address the issue as quickly as possible".

The spokesperson added: "The Lord Chancellor has already announced court buildings across the country will benefit from £220m for modernisation and repairs over the next two years."

This comes after many public buildings UK-wide were found to be made of RAAC, including schools, hospitals and police stations.

The Office of Government Property, Department of Education (DfE) and Local Government Association has shared information on the safety risks of RAAC.

Since 2018, they have encouraged those responsible for public buildings to conduct surveys to identify the material and take steps to have it removed if found.

The DfE said in a schools guidance document: "Sudden failure of RAAC panels in roofs, eaves, floors, walls and cladding systems would be dangerous, and the consequences could be serious."

RAAC, used in roofs, floors and walls between the 1950s and 1990s, has air bubbles inside it and a limited lifespan.

It was used as a cheaper alternative to standard building concrete.

The alarm was first raised about the potential dangers of RAAC, or Siporex, after the roof of a primary school in Kent gave way in 2018.

A leaked email sent to Downing Street from senior DfE officials in December last year said many school buildings now posed a "risk to life" as a result of the presence of crumbling concrete.

The Health and Safety Executive website warned that those responsible for the management, maintenance or alternation of central and local government buildings should know whether their buildings contain RAAC and act to ensure they are safe.