(1)A member of Her Majesty’s forces on duty or a constable may stop a person for so long as is necessary to question him to ascertain his identity and movements.
(2)A member of Her Majesty’s forces on duty may stop a person for so long as is necessary to question him to ascertain—
(a)what he knows about a recent explosion or another recent incident endangering life;
(b)what he knows about a person killed or injured in a recent explosion or incident.
(3)A person commits an offence if he—
(a)fails to stop when required to do so under this section,
(b)refuses to answer a question addressed to him under this section, or
(c)fails to answer to the best of his knowledge and ability a question addressed to him under this section.
(4)A person guilty of an offence under this section shall be liable on summary conviction to a fine not exceeding level 5 on the standard scale.
(5)A power to stop a person under this section includes a power to stop a vehicle (other than an aircraft which is airborne).