When must a tractor or works vehicle be fitted with a rear-view mirror?

A rear-view mirror is not required in a tractor or works vehicle.
A rear-view mirror must be fitted only when towing a trailer over 8 metres long.
A rear-view mirror must always be fitted.
A rear-view mirror must be fitted only when towing a trailer.

Explantion: All vehicles used on a public road must have a rear-view mirror. The mirror should be used to enable the driver to see the traffic and road conditions behind and to each side.

Theory Tester

When must a tractor or works vehicle be fitted with a rear-view mirror?

Control of Vehicle