UK ANO
From SI 1987 no 1812
(4) For rule 10 there shall be substituted the following —
"Failure of navigation and anti-collision lights
10—(1) In the United Kingdom, in the event of the failure of any light which is required by these Rules to be displayed at night, if the light cannot be immediately repaired or replaced the aircraft shall not depart from the aerodrome and, if in flight, shall land as soon as in the opinion of the commander of the aircraft it can safely do so, unless authorised by the appropriate air traffic control unit to continue its flight.
(2) In the United Kingdom, in the event of a failure of an anti-collision light when flying by day, an aircraft may continue to fly by day provided that the light is repaired at the earliest practicable opportunity." .
From Manual of Air Traffic Services CAP493
18 Failure of Navigation Lights
The pilot of an aircraft which has experienced a failure of one or more navigation lights may, in accordance with the RoA, request permission to continue the flight to destination. Controllers should take the following into consideration before authorising the flight:
a) Normally permission should be granted if flight is to be continued wholly within UK controlled airspace. Flight outside the UK under these conditions may not be authorised unless permission to continue has been obtained from the adjacent controlling authority;
b) If the pilot’s intention is to fly outside controlled airspace he should be instructed to land at the nearest suitable aerodrome. Selection of this aerodrome is the responsibility of the pilot although he may request information to assist him in making his decision. Under certain circumstances the pilot may decide that the nearest suitable aerodrome is his original destination.