MOT and Number Plates
Your MOT tester will examine your number plates carefully during the test. But what exactly are they checking? What causes plates to fail MOT? Is there any risk that a quality plate might fail the test? This guide walks through exactly what MOT inspectors look for, how the inspection process works, and how to ensure your plates pass MOT every single time without any issues or complications.
What MOT Testers Actually Check On Number Plates
MOT testing of number plates is actually fairly straightforward. The tester isn't looking for technical compliance with BSAU 145e, though that's implied. The tester is looking for practical functionality. Can the plate be read? Is it damaged? Is it properly mounted? These are the core checks. Readability is the first check. The tester looks at your plate and asks a simple question: can I read every character clearly? Every single character must be visible and readable. Not partially visible. Not faded. Clearly readable. The tester is assessing whether a human can read your registration with no difficulty. If characters are hard to read due to fading, crazing, or damage, the plate fails readability and the test is failed. Damage is the second check. The tester looks for cracks in the acrylic. Missing sections of the plate. Physical damage from impacts or accidents. Significant crazing, the fine cracking that happens to aged acrylic. Surface damage that affects the integrity of the plate. A plate with minor cosmetic damage might pass. A plate with significant structural damage fails. Reflectivity is the third check. The tester uses a reflectivity meter to measure whether your plate still reflects light properly. This is important because reflectivity ensures ANPR cameras can read your plate at night and in poor visibility. A plate that's lost reflectivity fails this check. Quality plates maintain reflectivity for years. Budget plates or very old plates sometimes lose reflectivity and fail. The registration mark check is fourth. Is the GB symbol present? Is the overall registration mark clear and correct? Is the format right? Missing elements or incorrect formatting causes failure. A genuine plate with correct format passes easily. Mounting security is fifth. Are the plates securely fitted to the vehicle? Loose plates, rattling plates, plates that move when you push them, all cause failure. Proper mounting with secure bolts and washers is required. Mounting is usually quick to fix if it's an issue. Obscuring is the final check. Is anything blocking or partially covering the plate? Dirty plates that are too dirty to read cause failure. Plate frames that obscure characters cause failure. Damage or deposits that cover characters cause failure. The plate must be completely visible and readable.
Character Readability Standards In Detail
Readability is the single most important check in MOT plate inspection. The tester reads each character individually. They start with the first character, read it, confirm they can identify it. They move to the second character, read it, confirm they can identify it. They continue through every character on the plate. If they can't clearly identify a character, the plate fails. This is simple and straightforward. The standard isn't based on some objective measurement. It's based on human judgment. Can a reasonable person read the plate easily? If yes, it passes. If no, it fails. This is why quality plates pass readability checks so easily. Quality plates have clear characters that are easy to read. Even if they're a bit aged, the characters are still clearly readable. Budget plates sometimes have characters that aren't as crisp, making them harder to read. Very old or degraded plates have faded characters that are hard to read. The tester isn't being unreasonably strict. They understand that plates age. They understand minor fading happens. But if fading is bad enough that characters become genuinely hard to read, the plate fails. This is actually a good standard because it ensures all plates on the road can be read by humans and by ANPR cameras.
Damage And Degradation Assessment
Damage assessment is straightforward. Cracks in the acrylic mean failure. If you can see a physical crack running through your plate, you'll fail MOT. Missing sections, parts of the plate that have broken off, mean failure. Chips and small breaks might not fail depending on severity. Crazing is the fine network of cracks that develops over time in acrylic, especially acrylic exposed to UV light and temperature extremes. Minor crazing doesn't cause failure. Severe crazing that affects readability might cause failure. Premium materials like gel resin resist crazing better than budget acrylic. Surface damage like scratches doesn't cause failure unless scratches obscure characters. A scratched plate that still reads clearly passes. A scratched plate where scratches obscure characters fails. The test is practical: can you read the plate? Not: does the plate look perfect? Fading is assessed. A plate that's faded but still clearly readable passes. A plate that's faded so badly that characters are hard to read fails. Quality plates fade slowly. Budget plates fade faster. Premium gel plates resist fading longer than standard acrylic. In general, damage serious enough to affect readability causes failure. Damage that doesn't affect readability passes. This is a reasonable standard that focuses on function, not appearance.
Reflectivity Requirements And Testing
Reflectivity testing is done with a reflectivity meter that measures how well your plate reflects light. BSAU 145e specifies minimum reflectivity values. The meter measures whether your plate meets these values. If reflectivity is below standard, the plate fails. Why does reflectivity matter? Because ANPR cameras read plates at night using reflected light. If reflectivity is poor, nighttime reading becomes difficult or impossible. You become effectively invisible to traffic enforcement, road charging, and law enforcement systems. That's a safety and legal issue. New quality plates easily meet reflectivity standards. Premium materials maintain reflectivity better than budget materials. After years of exposure, even quality plates eventually lose some reflectivity, but usually stay above the minimum standard. Very old plates or plates made with poor materials might fail reflectivity testing. If your plate fails reflectivity testing, you need a new plate. This is an actual compliance issue that needs fixing. You can't just accept it. Reflectivity is important for system functionality.
Registration Mark Verification And Requirements
The registration mark, the GB symbol area, has specific requirements. The GB symbol must be present. The EU blue background must be correct. The positioning of the registration mark on the plate must be correct. Missing or incorrect registration marks cause failure. This check is usually straightforward. If your plate is a genuine UK plate, the registration mark is correct. If you've somehow damaged or removed the registration mark, the plate fails. This is quick to assess visually.
Mounting Security And Installation Standards
Your plates must be securely mounted to the vehicle. Loose plates, plates that rattle, plates that move when you push on them, all cause failure. Secure mounting is required. This usually means two bolts per plate, one in each corner, with appropriate washers and security measures to prevent bolt theft. If your plates are loose, fixing them is easy. Tighten the bolts. If bolts are missing, replace them. Add locking bolts if needed. This is a quick fix if it's an issue. Most people have secure mounting, so this check passes easily. The mounting also needs to not obscure the plate. If the bolts or mounting hardware partially covers characters, the plate fails. Proper mounting positions hardware in the margins of the plate, not covering the registration number.
Obscuring Device Check And Clarity Requirements
Nothing can obscure or partially cover your registration number. Plate frames that cover characters cause failure. Some decorative frames are designed to not cover characters, and those are fine. But any frame that covers part of the registration fails. Dirt and contamination matter too. If your plate is so dirty that characters can't be read, the plate fails the obscuring check. This is preventable by keeping your plates reasonably clean. You don't need spotless plates, but dirty enough to make characters unreadable fails. Damage that covers characters causes failure. A broken piece of the plate hanging over characters. Paint or other substances covering the surface. Anything that prevents clear reading of characters causes failure.
Quality Plates Pass MOT Consistently And Easily
Properly manufactured quality plates pass MOT without issue. We have thousands of customers with our plates who have passed MOT. Zero failures due to plate quality. The reason is simple: quality plates are made to be readable, durable, and compliant. They pass MOT checks easily because they meet the practical standards that MOT testing assesses. Our plates are manufactured with durable materials that resist fading and crazing. Characters are clear and readable. Reflectivity is maintained. Plates are properly constructed and secure. Every quality standard that affects MOT passes easily. This is what you get when you buy from a quality manufacturer. Plates that work reliably in real-world use. Plates that pass MOT. Plates that work with ANPR systems. No surprises. No compliance issues. Just plates that work as expected.
FAQ
- How long do I have to fix a failed plate before next MOT?
If you fail MOT due to plates, you're given time to fix the issue and retest. You don't have to immediately replace the plate. Fix whatever the issue is, usually tightening mounting or replacing a damaged plate, and retest. - Can I appeal an MOT plate failure if I think it's wrong?
Yes. You can request a second opinion or get your plate checked by the manufacturer. If you believe the failure is unjustified, you can dispute it. - Will a slightly faded plate definitely fail?
Not necessarily. Slight fading doesn't cause failure if characters are still clearly readable. Only significant fading that makes characters hard to read causes failure. - Do all MOT testers check plates the same way?
Generally yes, they follow the same MOT standards. But individual judgment on subjective assessments like readability might vary slightly between testers. Overall standards are consistent. - What if my plate passes local MOT but would fail elsewhere?
MOT standards are national, so shouldn't vary by location. But if there's variation, the first test result is what matters. Get the specific issue fixed and pass the test.