Could Your Windscreen Sun Strip Be Illegal?

With temperatures rising across the UK and bright sunshine making driving uncomfortable, many motorists are turning to tinted windscreen sun strips to reduce glare and keep their cars cooler. But before you stick a dark strip across the top of your windscreen, it’s worth knowing that some sun strips and window tints could land you with an MOT failure, a police stop, or even a fine.

Here’s what UK drivers need to know about what’s legal, and what isn’t.

Why Drivers Use Sun Strips in Hot Weather

Sun strips have become increasingly popular during warm spells because they can:

• Reduce glare from low sun
• Help keep the cabin cooler
• Improve driving comfort on long journeys
• Give cars a sportier appearance

During summer heatwaves, they can genuinely make driving easier, especially during early mornings and evenings when the sun sits low in the sky.

But visibility laws still apply, regardless of the weather.

Are Windscreen Sun Strips Legal in the UK?

Yes, but only if they do not obstruct the driver’s view.

UK law focuses heavily on driver visibility. Anything fitted to the windscreen that significantly blocks your view of the road can be considered illegal or cause an MOT failure.

The front windscreen must allow at least 75% of light through, while the front side windows must allow at least 70% of light through.

That means:

• Very dark windscreen tints are illegal
• Thick or oversized sun strips can be illegal
• Adding tint film to already tinted factory glass can accidentally push you over the legal limit

How Big Can a Sun Strip Be?

There is no exact measurement written into UK law specifically for sun strips, but guidance generally states they should stay within the upper tinted area of the windscreen and not intrude into the driver’s primary field of vision.

Many installers recommend keeping sun strips within around 10cm to 15cm from the top edge of the windscreen. Anything deeper risks obstructing visibility, especially in smaller cars or for taller drivers.

A strip that dips too low could:

• Obstruct traffic lights
• Block road signs
• Interfere with visibility at junctions
• Cause an MOT advisory or failure

What Does the MOT Check?

During an MOT, testers inspect the windscreen and the driver’s field of vision. The MOT manual states that any obstruction that “significantly affects” the driver’s view through the swept area of the windscreen can result in a major defect.

The swept area is the part cleared by the windscreen wipers.

Testers also assess:

• Excessive tinting
• Stickers or decals
• Damage or discolouration
• Anything blocking mandatory mirrors

The most sensitive area is known as “Zone A”, the central section directly in front of the driver.

If a sun strip extends too far into this area, the vehicle may fail.

Can Police Stop You for Illegal Tints?

Absolutely.

Police and DVSA officers can carry out roadside tint checks using light meters. If your front windscreen or front side windows are too dark, you could receive:

• A prohibition notice
• A fixed penalty fine
• Penalty points in serious cases
• An order to remove the tint immediately

Drivers can even be prevented from continuing their journey until illegal tints are removed.

Factory Privacy Glass vs Aftermarket Tint

A common mistake is assuming a “light” aftermarket tint is automatically legal.

Most modern cars already have slightly tinted glass from the factory. Adding film on top can reduce light transmission far below the legal threshold.

This is why professional installers measure existing glass before applying tint film.

Rear windows and rear windscreens are different, they can legally be much darker in the UK.

Summer Driving Safety Matters

While sun strips can help during hot weather, visibility remains one of the biggest safety concerns during summer driving.

Bright sunlight already increases the risk of:

• Dazzle-related accidents
• Missed hazards
• Delayed reaction times
• Difficulty spotting cyclists and pedestrians

Adding an oversized or excessively dark sun strip can make those problems worse, especially at dawn, dusk, or during sudden weather changes.

The Safest Option

If you want a sun strip this summer, the safest approach is:

• Use a reputable installer
• Keep the strip narrow and high on the windscreen
• Avoid very dark tint films on front glass
• Check your visibility from the driving position
• Ensure the strip stays outside the main wiper sweep area

A professionally fitted, modest sun strip can still reduce glare without risking MOT trouble.

Final Word

Tinted sun strips might look good and help keep your car cooler during the current hot weather, but UK motorists should be careful not to cross the line into illegal visibility obstruction.

If you’re unsure whether your windscreen tint or sun strip is legal, it’s worth getting it checked before your next MOT, or before the police check it for you.