An "authorised officer" is—
A National Crime Agency officer, prison officer, or any other person who has the powers of a constable (but is not a constable)—
These expressions have the meanings given—
"extradition transit powers" means the powers under—
(a)section 189A (except the power to issue transit certificates), and
(b)section 189B;
"foreign territory" means a territory outside the United Kingdom;
"non-UK extradition" means extradition from one foreign territory to another foreign territory;
"relevant search power" means a power of search under—
(a)section 189A(2)(c) or (d), or
(b)section 189B(2)(b) or (c);
"relevant UK authority" means—
(a)the National Crime Agency (in the case of a non-UK extradition to a category 1 territory), or
(b)the Secretary of State (in any other case).
A reference to the transit of a person through the United Kingdom is a reference to the person arriving in, being in, and departing from the United Kingdom (whether or not the person travels within the United Kingdom between arrival and departure).
This section applies for the purposes of section 189A to 189D (and this section).