Commentary on Sections Part 4: Enforcement of Sentences and Orders Section 47: Custody of prisoner in transit etc.
79.This section enables an ICC prisoner to be held in lawful custody by domestic authorities whilst outside prison, whether he is in the UK or on board a British vessel or aircraft. This would include, for example, while the prisoner is in transit between the UK and the ICC. Subsection (4) grants the powers of a constable to a person designated by the Secretary of State to take the prisoner to or from any place, or to keep the prisoner in custody, and provides for equivalent authority, protection and privileges.
80.Subsection (5) allows the arrest of any ICC prisoner who escapes or is unlawfully at large, including an ICC prisoner who escapes from prison in any part of the UK. Any constable (including someone granted custodial powers under subsection (4)), has the authority to arrest the fugitive prisoner without warrant.