Article 9 Other exemptions
The controls specified in article 3(1) and (2) do not apply in respect of a person causing a vehicle to stop if that person is—
required by law to cause the vehicle to stop or not to proceed;
obliged to stop the vehicle so as to avoid an accident;
prevented from proceeding in the vehicle by circumstances beyond the person’s control;
getting or giving help in consequence of an accident or an emergency, or otherwise taking action for public safety;
using the vehicle for fire brigade, ambulance or police purposes;
using the vehicle in connection with the removal of any obstruction to traffic;
using the vehicle in connection with the maintenance, improvement or reconstruction of any length of road specified in schedule 1;
The controls specified in article 3(1) and (2) do not apply to anything done with the permission or at the direction of a police constable in uniform or a traffic warden.