67 Emergencies and temporary obstructions.E+W+S
(1)A constable, or a person acting under the instructions (whether general or specific) of the chief officer of police, may place on a [highway][road], or on any structure on a [highway][road], traffic signs (of any size, colour and type prescribed or authorised under section 64 of this Act), indicating prohibitions, restrictions or requirements relating to vehicular traffic, as may be necessary or expedient to prevent or mitigate congestion or obstruction of traffic, or danger to or from traffic, in consequence of extraordinary circumstances; and the power to place signs conferred by this subsection shall include power to maintain a sign for a period of 7 days or less from the time when it was placed, but no longer.
(2)[Section 36 of the Road Traffic Act 1988] (drivers to comply with traffic directions) shall apply to signs placed in the exercise of the powers conferred by subsection (1) above.
(3)Regulations under section 64 of this Act prescribing any type of object or device for warning traffic of a temporary obstruction may include provisions for authorising (subject to such conditions as may be specified in the regulations) persons not otherwise authorised to do so to place an object or device of that type on or near roads, or on or near any description of road so specified, in such circumstances and for such periods as may be so specified.