Yes, a cracked mirror can fail an MOT in the UK if the damage affects rearward visibility, creates sharp edges, leaves the mirror insecure or prevents proper adjustment. This UK mechanic-style guide explains mirror MOT rules, visibility risks and common failure points.
A cracked mirror can fail an MOT if the glass is missing, the view is badly distorted, the mirror is loose, cannot be adjusted properly, has sharp edges or leaves the driver without adequate rearward visibility.
A small crack may pass if the mirror remains secure and still gives a clear view, but replacing damaged mirror glass before the test is usually the safer option.
A mirror is not there for appearance. It helps the driver judge traffic behind and beside the car. If cracks split the reflection or make vehicles hard to judge, the mirror should be repaired before MOT.
The tester is mainly looking at visibility, security and safety.
Cracked or damaged glass may stop the driver seeing clearly behind or beside the vehicle.
Missing glass is much more likely to fail because the mirror cannot provide its intended view.
A loose mirror housing or glass can fail if it is not safely attached.
Broken glass or plastic with sharp edges can be treated as dangerous.
The vehicle must still provide adequate rearward visibility through the required mirrors.
A mirror stuck in the wrong position may not give the driver a usable view.
A small crack or cosmetic mark may not automatically fail if the mirror remains secure, adjustable and gives a clear rearward view without dangerous edges.
However, if the crack distracts the driver, splits the reflection, makes vehicles hard to judge or leaves loose glass, repair it before the MOT.
The MOT is concerned with whether the driver has the required rearward view.
Important for rearward and side visibility. Damage on this side is more likely to affect safe driving.
May be required depending on the vehicle setup, especially if rear visibility is restricted.
Must be usable where fitted and required. Obstructed rear windows can make exterior mirrors more important.
Electrical folding is not usually the key issue. The mirror must be secure and provide the required view.
Adjust the mirror as you normally would. If the crack makes it hard to judge traffic behind, lane position or reversing distance, it is not worth risking. A mirror that technically remains attached but gives a poor view is still a problem.
Also check whether the mirror vibrates when the door shuts. Loose glass can fall out later.
Usually, yes. Mirror damage is often simple and relatively inexpensive to repair compared with the inconvenience of an MOT failure.
If only the glass is damaged, replacement stick-on or clip-in mirror glass may be enough. If the housing is broken, loose, sharp or no longer holds position, the full mirror assembly may need repair or replacement.
Stick-on mirror glass can be acceptable if it is fitted securely, gives a clear view and does not distort the reflection. It should not be loose, badly shaped, cracked or placed over broken glass in a way that makes the view unclear.
Read car repair costs guide →Driving with a badly cracked, missing or loose mirror can reduce visibility and make lane changes, reversing, parking and joining traffic more dangerous.
If the mirror no longer gives a clear view, repair it before driving regularly and before presenting the vehicle for MOT.
Most cracked mirrors happen from tight parking spaces, clipped wing mirrors, door impacts, vandalism, icy conditions or previous poor repairs. After impact, check the casing and adjustment mechanism, not just the glass.
Common questions UK drivers ask about cracked wing mirrors, missing glass, mirror housings and stick-on mirror repairs.
It can if the crack affects visibility, the mirror is insecure or sharp edges are present.
Possibly, if the view is still clear and the mirror is secure, but repair is safer.
It is much more likely to fail if the vehicle no longer has the required rearward view.
It can if the casing is loose, insecure or has dangerous sharp edges.
It may be acceptable if it is secure, correctly fitted and gives a clear view.
Yes, especially if the damage affects visibility, adjustment, security or safety.
Motor Vehicle Expert publishes practical UK-focused vehicle diagnostics, maintenance, MOT, used car and repair cost guidance based on common driver questions and real-world garage situations.
