ensure all sidelights and rear registration plate lights are lit between sunset and sunrise
use headlights at night, except on a road which has lit street lighting. These roads are generally restricted to a speed limit of 30 mph (48 km/h) unless otherwise specified
use headlights when visibility is seriously reduced
Night (the hours of darkness) is deemed to be the period between half an hour after sunset and half an hour before sunrise).
use any lights in a way which would dazzle or cause discomfort to other road users, including pedestrians, cyclists and horse riders
use front or rear fog lights unless visibility is seriously reduced. You MUST switch them off when visibility improves to avoid dazzling other road users.
In stationary queues of traffic, drivers should apply the parking brake and, once the following traffic has stopped, take their foot off the footbrake to deactivate the vehicle brake lights. This will minimise glare to road users behind until the traffic moves again.
You should also
use dipped headlights, or dim-dip if fitted, at night in built-up areas and in dull daytime weather, to ensure that you can be seen
keep your headlights dipped when overtaking until you are level with the other vehicle and then change to main beam if necessary, unless this would dazzle oncoming road users
slow down, and if necessary stop, if you are dazzled by oncoming headlights
Hazard warning lights.
These may be used when your vehicle is stationary, to warn others that you are temporarily obstructing traffic. Never use them as an excuse for dangerous or illegal parking. You must not use hazard warning lights whilst driving or being towed unless you are on a motorway or an unrestricted dual carriageway and you need to warn drivers behind you of a hazard or obstruction ahead. Only use them for long enough to ensure that your warning has been observed.