5. c. 11; long title An Act to make perpetual, subject to an amendment, the Special Constables Act, 1914; to provide for the employment of special constables in connection with Naval, Military and Air Force yards and stations; and to remove certain limitations on the appointment of special constables in Scotland.)

[1] It made permanent an earlier act on special constables passed in 1914.

A member of either House then had 21 sitting days after that date to lay an address before the Crown for the repeal of any regulations made by that Order in Council.

Such regulations would be made void "without prejudice to the validity of any proceedings which may in the meantime have been taken thereunder or to the making of any new regulations provided that Orders in Council under the said Act shall not be deemed to be statutory rules within the meaning of section one of the Rules Publication Act, 1893."

This led to the establishment of the Royal Marine Police, the Army Department Constabulary and the Air Ministry Constabulary over the course of the 1920s - these were later all subsumed into the Ministry of Defence Police.