The Prison Service is to seek formal Building Regulations approval for new prisons for the first time in an effort to prove they are safe.

The service has crown immunity, which means it does not have to comply with regulations. Previously it got contractors to self-certify their work but will now appoint private approved inspectors to check and sign off work.

Les James, the service’s senior health and safety manager of custodial property, said: “We want the crown to be seen to be as compliant with the Building Regulations as private industry.”

Calls were made for immunity rules to be changed after a fire destroyed a three-month-old detention centre in Bedfordshire in 2002 that had not been fitted with sprinklers.

James said the move had also been prompted by changes to fire safety legislation. Firms including HCD Building Control and Butler and Young have advised the service on implementing the changes, which are expected to take effect at the end of July.

The changes will also affect the proposed Titan prisons, a consultation on which was launched at the end of last week. Galliford Try, Bouygues, Wates and Interserve are among those that have been contacted to comment on the proposals.