The rules for tinted front windscreens and front side windows depend on when the vehicle was first used. There are no rules for tinting the rear windscreen or rear passenger windows.
The front windscreen must let at least 75% of light through and the front side windows must let at least 70% of light through.
The front windscreen and front side windows must both let at least 70% of light through.
It’s illegal to fit or sell glass (or a vehicle already fitted with glass) that breaks the rules on tinted windows.
The police or VOSA vehicle examiners use light measuring equipment to measure window tint.
Above 30% Visible Light Transmission (Less Severe Window Tints)
The owner or driver of such a vehicle will be required to have the tinted film removed from the windows under the direction of either a Rectification Notice or a Delayed Prohibition Notice, A period of grace will apply for a limited number of days (normally ten) during which time the vehicle may be driven whilst the rectification work is to be completed. In either case, the vehicle will need to be inspected by either a Police Officer or Vehicle Inspectorate Officer to confirm that the glass has been restored to a compliant condition. Prosecution is unlikely in such circumstances provided the vehicle owner complies fully.
Below 30% Visible Light Transmission (Excessively dark Window Tints)
The owner or driver of such a vehicle may be issued with an Immediate Prohibition Notice and immediately prevented from driving the vehicle on public roads until the tints have been removed and either a Police Officer or Vehicle Inspectorate Officer confirms that the glass has been restored to a compliant condition. It is also possible, depending on the severity of the offence, that the owner may be prosecuted for driving a vehicle in a non-roadworthy or even a dangerous condition with the potential for Penalty Points and a Fine. Driving such a vehicle on public roads before the tints have been removed and before a Prohibition Notice has been lifted will be a serious offence and the owner or driver is likely to be prosecuted
Tinted windows are not part of the MOT test.
Above mentioned rules show how dark and which windows can be tinted for car to be road legal, however it doesn`t mean that you can tint front windows. As shown on these images, most of the windows are tinted from factory and by applying on them any kind of tinting film will make your car illegal to drive on road.
Window tinting is also classed as a vehicle modification so you should inform your vehicle insurer. Do be aware that if you have your front door windows tinted and you have an accident, it could possibly be a get out clause for your insurance company