Following changes to intervention powers introduced by the Education and Adoption Act 2016, the Department for Education has released guidance (external link) on the powers that can be taken in respect of a Pupil Referral Unit (PRU).
The Secretary of State now has a duty to make an academy order in respect of a PRU that has been judged 'inadequate' by Ofsted. This duty will apply to PRUs judged inadequate prior to 27 June 2016as well as to PRUs that are judged inadequate subsequently.
Once made, the academy order can only be revoked by the Secretary of State in exceptional circumstances such as where a PRU is deemed to be no longer being viable and therefore making it more appropriate for it to close.