The windscreen chip law is part of the U.K.'s annual vehicle inspection for motor vehicles over three years of age. The entire windscreen of a vehicle is checked for chips and cracks.
The Ministry of Transport test is administered at testing stations throughout the U.K. to check a motor vehicle for road safety and that it meets environmental emissions standards. Cracks and chips on a windscreen can result in a failed MOT test, meaning repairs must take place before the vehicle can be driven on roads in the U.K.
The windscreen chip law divides a vehicle windshield into two zones, zone A is 11.5 inches on the drivers side of the vehicle centred on the steering column. The rest of the windscreen is subject to less stringent windscreen chip regulations.
Chips of 0.4 inches or greater in zone A of a windscreen will result in a failed MOT test and must be repaired before the test can be passed. On the rest of the windshield chips and cracks of 1.6 inches or greater result in a failed MOT test.