(1)An area is a cordoned area for the purposes of this Act if it is designated under this section.
(2)A designation may be made only if the person making it considers it expedient for the purposes of a terrorist investigation.
(3)If a designation is made orally, the person making it shall confirm it in writing as soon as is reasonably practicable.
(4)The person making a designation shall arrange for the demarcation of the cordoned area, so far as is reasonably practicable—
(a)by means of tape marked with the word “police”, or
(b)in such other manner as a constable considers appropriate.