23.—(1) Subject to section 83ZC of the Act and rule 24, a naval or air-force officer falling within paragraph (2) shall be qualified under that section for membership of the court for the purposes of hearing an appeal if the court administration officer considers that the necessary number of military officers so qualified is not (with due regard to the public service) available to sit as members of the court for the purposes of that hearing.
(2) A naval or air-force officer falls within this paragraph if he has held a commission in any of Her Majesty’s naval, military or air forces for a period of not less than two years or for periods amounting in the aggregate to not less than two years.
(3) In this rule—
“air-force officer” means an officer belonging to Her Majesty’s air forces and subject to air force law; and
“naval officer” means an officer belonging to Her Majesty’s naval forces and subject to the Naval Discipline Act 1957.