(1)A member of the Territorial Army shall not be liable to be called out under section 11(1) above unless there is in force an order of Her Majesty, signified under the hand of the Secretary of State, authorising the calling out under that section of members of the Territorial Army.
(2)An order in force under subsection (1) above may be revoked by an order of Her Majesty signified as there mentioned, but the revocation shall not affect the liability for service of any person called out for service by virtue of the order at the time of its revocation.