Immigration

On its true construction, s 36(1) of the UK Borders Act 2007 referred to persons who had served such periods of imprisonment as they were required to serve pursuant to a custodial sentence.

There could be no duality of detention: either the foreign national prisoner had served a term of imprisonment and was detained under s 36 of the Act, or he had not served a term of imprisonment and was still a serving prisoner.

The two could not overlap. Section 36 of the Act was concerned with the ability to keep a foreign national prisoner who had been sentenced to imprisonment for 12 months or longer in detention in circumstances where he might otherwise be released. Prior to that time, he had been a serving prisoner, so there was no need to exercise any power to detain under s 36.

The concern arose in circumstances where a foreign national prisoner was going to be released but the