Can you drive with a cracked windscreen? UK MOT rules explained

Short answer: a small chip outside the driver’s line of sight doesn’t usually stop you driving, but damage in front of the driver can fail the MOT and make the car unsafe to drive. At the MOT, damage bigger than 10mm in Zone A (a 290mm-wide area centred on the steering wheel) or bigger than 40mm in the rest of the area the wipers sweep can fail, if it significantly affects the driver’s view of the road.

Last reviewed: 20 October 2026, by South Wales Windscreens. This guide summarises official guidance; it isn’t legal advice.

The MOT windscreen rules

The MOT inspection manual on GOV.UK (section 3.2, condition of glass) tells testers to check the windscreen and the windows on either side of the driver’s seat from the driver’s seat. They look for:

MOT windscreen damage limits

Area of the windscreen	Damage that can fail
Zone A – 290mm wide, centred on the steering wheel, within the swept area	More than 10mm in diameter
The rest of the swept area (where the wipers clear)	More than 40mm in diameter
Windows on either side of the driver’s seat	Damage or excessive tinting that affects the driver’s view

The manual also says:

• failure for damage is only justified if the damage significantly affects the driver’s view of the road;
• a repaired windscreen is judged only on whether the repair interferes with vision – an “invisible” or barely detectable repair, finished flush with the surrounding glass, doesn’t count as damage;
• damage that affects the driver’s view of the road is recorded as a major defect, and a windscreen in such a condition that visibility through the swept area is seriously affected is dangerous.

The same manual covers cars and light vans: class 4 includes goods vehicles up to 3,000kg, and class 7 covers goods vehicles from 3,001kg to 3,500kg (MOT inspection manual introduction).

What the Highway Code says

Annex 6 of the Highway Code says windscreens and windows must be kept clean and free from obstructions to vision. A crack across your line of sight is exactly the kind of thing that can obstruct your view.

Driving after an MOT failure

According to GOV.UK’s guidance on what happens after the MOT, you can only drive away a vehicle that has failed if your current MOT is still valid and no “dangerous” problems were listed – and it must still meet the minimum standards of roadworthiness at all times. GOV.UK says you can be fined up to £2,500, be banned from driving and get 3 penalty points for driving a vehicle that has failed its MOT because of a “dangerous” problem.

Repair or replace?

• Chips up to the size of a £1 coin can usually be repaired with resin, typically in around 20 minutes. See windscreen chip repair.
• Anything larger, a chip that has spread into a crack, or damage right in the driver’s line of sight usually means a windscreen replacement. Fitting is usually under an hour, and you can drive away about an hour after fitting.

A chip that’s inside the MOT limits today can spread with road vibration and temperature changes, so repairing it early is the cheapest way to stay within them.

Get it checked

Not sure which side of the line your damage is? WhatsApp us a photo with a £1 coin next to it and we’ll tell you whether it can be repaired. We come to you anywhere in all CF and NP postcodes, plus Swansea & Neath (SA1–SA12) and Brecon (LD3), with no call-out charge.

Questions about cracked windscreens

Sources

• GOV.UK – MOT inspection manual: cars and passenger vehicles, 3. Visibility
• GOV.UK – MOT inspection manual: introduction (vehicle classes)
• GOV.UK – The Highway Code, Annex 6: vehicle maintenance, safety and security
• GOV.UK – Getting an MOT: after the test