The Extradition (Tokyo Convention) Order 1997

Article 6

1.  The aircraft commander may, when he has reasonable grounds to believe that a person has committed, or is about to commit, on board the aircraft, an offence or act contemplated by Article 1, paragraph 1, impose upon such person reasonable measures including restraint which are necessary:

(a) to protect the safety of the aircraft, or of persons or property therein; or

(b) to maintain good order and discipline on board; or

(c) to enable him to deliver such person to competent authorities or to disembark him in accordance with the provisions of this chapter.

2.  The aircraft commander may require or authorize the assistance of other crew members and may request or authorize, but not require, the assistance of passengers to restrain any person whom he is entitled to restrain. Any crew member or passenger may also take reasonable preventative measures without such authorization when he has reasonable grounds to believe that such action is immediately necessary to protect the safety of the aircraft, or of persons or property therein.