Side and rear lamps:

Vehicles not fitted with any front or rear position lamps (side/rear lamps) don't need to be fitted with any other lamps or rear reflectors (this covers rally/competition vehicles etc which are only used during daylight hours) but if fitted they get tested.  For example a vehicle which is used only during daylight as above may have a set of stop lamps. If these are defective then the vehicle will fail the test. Therefore the owner has two options, either fix the fault on the stop lamps or remove them altogether in order to pass the re-test.

Front side lamps must be white unless they are inside a yellow headlamp, must not flicker when tapped by hand and other lights must not affect their operation, except as mentioned below.

Rear lamps must show a steady red light, not flicker when tapped and must not be affected by other lamp circuits but vehicles first used before 1st September 1965 may have stop lamps or direction indicators incorporated into the front and rear lamps.

The lens can be repaired using a proprietary repair tape but must satisfy requirements for security, colour, light output and durability. The important point is whether the lamp continues to perform its function.

At least 50% of the front/rear position lamp area must be visible. This accounts for structural features of the vehicle (i.e security vehicles, off-roaders etc)