How to Appeal a Yellow Box Junction PCN

Yellow Box Junction PCNs are one of the most aggressively enforced traffic penalties in the UK — but also one of the easiest to overturn when you understand the legal test. Councils and TfL issue hundreds of thousands of these fines each year, and most drivers wrongly assume that “being in the box” automatically means the PCN is valid. It doesn’t.
 
Yellow Box contraventions rely on one very specific legal requirement, and councils frequently misapply it or misinterpret the CCTV footage. With the correct approach, many Yellow Box PCNs can be cancelled at the first challenge stage.
 
This guide gives you the clear, step-by-step method to challenge a Yellow Box PCN successfully and positions Smart Appeal as a credible authority in the UK for PCN guidance.

The Legal Test for a Yellow Box Contravention

 A Yellow Box contravention only occurs if both of these are true:
- Your exit was not clear when you entered the box
- You stopped due to stationary vehicles inside the box

Valid Grounds to Appeal

Your exit was clear at the time of entry.

Drivers are allowed to proceed into a Yellow Box if there is a reasonable expectation that they will clear it. The law does not require the exit to remain clear throughout the entire manoeuvre — only at the point of entry. This is where councils can get it wrong. Many PCNs show a still image of a vehicle stopped in the box, but they do not reflect what the driver saw seconds earlier. Adjudicators consistently agree that if the gap ahead existed when the driver committed, even if it closed due to traffic unpredictability, the alleged contravention did not take place. This is the strongest winning argument. For e.g.
 
1. The vehicle in front stopped unexpectedly. Unexpected braking is one of the most common real-world situations that leads to unjust PCNs. A driver ahead may hesitate, swerve slightly, slow suddenly for a pedestrian or attempt a last-second lane change. These are all external factors outside your control. The regulations do not punish drivers for the behaviour of others. If the reason you stopped was a driver’s hesitation — not stationary traffic already blocking the exit — the PCN should not stand. 

2. CCTV does not show the full manoeuvre  
Many councils fail to include the full video, instead relying on two or three still photographs taken several seconds apart. Still images cannot prove what the driver saw upon entry, nor can they demonstrate that stationary vehicles caused the stop. If the council’s video begins only after your vehicle has already entered the box, the evidence is incomplete and the PCN becomes challengeable. Full-motion footage showing the entire sequence is essential for a lawful enforcement. 
 
3. The Yellow Box is incorrectly marked  
A surprising number of Yellow Boxes in the UK are not compliant with DfT diagrams 1043 and 1044. Common defects include boxes that extend beyond the junction, boxes painted too wide for the road layout, boxes covering parts of pedestrian crossings, or boxes with angles that do not meet regulatory standards. If any marking deviates materially from the approved diagrams, the enforcement becomes questionable. Tribunals have cancelled PCNs where markings were shown to be misleading or excessively large.
 
4. Road layout or signalling forced you into the box  

5. Poorly designed junctions can cause invalid PCNs.

Evidence You Should Gather

- Full CCTV video
- Photos of the junction layout
- Proof your exit was clear at entry
- Evidence of sudden braking
- Photos of non-compliant markings

How to Structure a Yellow Box PCN Appeal
 
Start with your PCN and vehicle details  
Explain why the contravention did not occur; Add supporting evidence  

A strong appeal benefits from a short, clear explanation written in your own words. For example:

“When I entered the junction, my exit lane was fully clear and moving. The car in front braked abruptly due to merging traffic, which could not have been anticipated. The CCTV still images do not show my point of entry, and the video provided does not include the approach. Based on this, the contravention did not occur. Please cancel this PCN.”

 

Including a simple narrative like this helps councils understand the sequence of events and increases your likelihood of success.

Request cancellation politely