In this Act, "an ETA" means an authorisation in electronic form to travel to the United Kingdom.
Immigration rules may require an individual of a description specified in the rules not to travel to the United Kingdom from any place (including a place in the common travel area), whether with a view to entering the United Kingdom or to passing through it without entering, unless the individual has an ETA that is valid for the individual's journey to the United Kingdom.
The rules may not impose this requirement on an individual if—
In relation to an individual travelling to the United Kingdom on a local journey from a place in the common travel area, subsection (3)(b) applies only if the individual would also be entitled to enter without leave if the journey were instead from a place outside the common travel area.
The rules may impose the requirement mentioned in subsection (2) on an individual who—
only if it appears to the Secretary of State necessary to do so by reason of differences between the immigration laws of the United Kingdom and that island.
The rules must—
The rules may also—
Rules made by virtue of this section may make different provision for different cases or descriptions of case.