Commentary on Sections Part 3.Miscellaneous Section 56: Re-entry into Northern Ireland of offender removed under section 55
This Section provides for how a prisoner removed early from prison is to be treated should they return to Northern Ireland at a later date.    Subsection (2) provides for a person returning to Northern Ireland before their original sentence expiry date to be detained in pursuance of their sentence for a period of time equal in length to the outstanding custodial period or until their sentence expiry date, whichever is sooner.
Subsection (3) provides a constable with a power to arrest without warrant any person suspected of being liable to be detained by virtue of subsection (2) and to take that person to a place where that person can be detained.
Subsection (4) provides for a person so detained by virtue of subsection (2) to be unable to be removed again under Section 43. Subsection (5) provides for a person detained under the provisions of subsection (2) to be released by whichever of the two dates specified in subsection (2) is the earlier.
Subsection (6) sets out definitions of “further custodial period”, “outstanding custodial period” and “sentence expiry date”