A Minister of the Crown may by regulations make such provision as the Minister considers appropriate for the purpose of implementing any of the following—
Article 20(1), (3) and (4) of the withdrawal agreement (restrictions of the rights of entry and residence);
Article 19(1), (3) and (4) of the EEA EFTA separation agreement (restrictions of the rights of entry and residence);
Articles 17(1) and (3) and 20(3) of the Swiss citizens' rights agreement (restrictions of the rights of entry and residence).
If the Minister considers it appropriate, regulations under subsection (1) relating to the implementation of a provision mentioned in subsection (1)(a), (b) or (c) may be made so as to apply both to—
persons to whom the provision in question applies, and
persons to whom that provision does not apply but who—
have entry clearance granted by virtue of relevant entry clearance immigration rules (see section 17),
have leave to enter or remain in the United Kingdom granted by virtue of residence scheme immigration rules (see section 17), or
otherwise have leave to enter granted after arriving with entry clearance granted by virtue of relevant entry clearance immigration rules.
In subsection (2)(b), references to a person who has entry clearance or leave to enter or remain include references to a person who would have had entry clearance or leave to enter or remain but for—
the making of a deportation order under section 5(1) of the Immigration Act 1971, or
the making of any other decision made in connection with restricting the right of the person to enter the United Kingdom.
The power to make regulations under subsection (1) may (among other things) be exercised by modifying any provision made—
by or under the Immigration Acts, or
under other primary legislation.