http://www.legislation.gov.uk/uksi/1997/21/article/9/madeThe A2 Trunk Road (Greenwich) Red Route (Clearway) Traffic Order 1997Roads and highwaysBusesVehiclesTaxi and minicab licencesRoad and pathway maintenanceKing's Printer of Acts of Parliament2011-07-04ROAD TRAFFIC
Other exemptions
9
1
The controls specified in article 3(1) do not apply in respect of a person causing a vehicle to stop if that person is—
a
required by law to cause the vehicle to stop or not to proceed;
b
obliged to stop the vehicle so as to avoid an accident;
c
prevented from proceeding in the vehicle by circumstances beyond the person’s control;
d
getting or giving help in consequence of an accident or an emergency, or otherwise taking action for public safety;
e
opening or closing a gate or other barrier at the entrance to premises to which the vehicle is being driven or from which it has emerged if it is not reasonably practicable to cause the vehicle to stop elsewhere for the purpose;
f
using the vehicle for fire brigade, ambulance or police purposes;
g
using the vehicle in connection with the removal of any obstruction to traffic;
h
using the vehicle in connection with the maintenance, improvement or reconstruction of any length of road specified in schedule 1;
i
using the vehicle under a licence under section 6 of the Metropolitan Public Carriage Act 1869 to stop for so long only as may be required to enable a passenger to get on or off the vehicle; or
j
using a disabled person’s vehicle which displays a disabled person’s badge in the relevant position to stop for so long only as may be required to enable a disabled person to get on or off the vehicle.
2
The controls specified in article 3(1) do not apply in respect of a vehicle which bears the Royal Mail livery which is waiting at the edge of a carriageway for as long as may be necessary for the purpose of collecting or delivering letters in pursuance of any statutory duty of the Post Office to collect or deliver letters.
3
The controls specified in article 3(1) do not apply to anything done with the permission or at the direction of a police constable in uniform or a traffic warden.
1869 c. 115.