Camera Warning Sign (Diagram 878)
Summary
Speed cameras on UK roads must be preceded by a warning sign — specifically Diagram 878 under the Traffic Signs Regulations and General Directions 2016. The Association of Chief Police Officers (ACPO) Camera Guidance and the DfT's 'Safety Camera' guidelines require the warning sign to be erected and visible before the camera location. A missing, obscured, or non-compliant Diagram 878 sign does not automatically void the prosecution, but it is a material factor in tribunal and court proceedings — adjudicators regularly allow traffic contravention appeals where the mandatory warning sign was absent.
What Diagram 878 requires
Diagram 878 is the triangular warning sign showing a camera symbol, used to alert drivers to a speed camera ahead. TSRGD 2016 specifies the exact dimensions, reflectivity, and placement requirements. The sign must be placed at the prescribed distance before the camera — typically 500–750 metres on a 70 mph road, closer on lower-speed roads. The sign must be unobstructed, legible at the approach distance, and facing oncoming traffic. Placement on the wrong side of the road or obscured by vegetation can constitute a defect.
The legal significance of a missing warning sign
There is no statutory provision that automatically voids a speeding prosecution because a camera warning sign is missing. However, the Crown Prosecution Service guidance and police camera partnerships treat the warning sign as part of fair operation. In traffic contravention proceedings (for civil bus lane or moving traffic cameras), adjudicators apply a reasonableness and procedural fairness test. For criminal speeding prosecutions, a missing warning sign can support a submission of no case to answer or a mitigation argument, particularly if combined with other procedural defects.
Fixed vs mobile cameras
Diagram 878 signs are primarily relevant to fixed Gatso, Truvelo, and average-speed cameras. Mobile speed cameras (operated by an officer or vehicle) have different siting requirements — there must generally be adequate visibility of the speed limit signs, but the Diagram 878 requirement is less rigid. Average speed cameras (SPECS) require warning signs at the start of the enforcement zone.
Checking the camera warning sign for your case
- ✓Visit the camera location (or use Google Street View) and photograph all signs in the approach.
- ✓Identify the Diagram 878 sign — is it present, correctly sited, and visible?
- ✓Check the distance from the sign to the camera against TSRGD requirements for the road type.
- ✓Note any obstructions: vegetation, parked vehicles, roadworks.
- ✓If the sign is missing or defective, photograph and document — this is grounds for appeal.
Combining with other appeal grounds
A missing camera warning sign is most powerful when combined with other procedural defects — a late NIP, a defective speed limit TRO, or ANPR misidentification. A single defect standing alone may not succeed; multiple overlapping defects significantly improve the strength of an appeal.
Sources
- Traffic Signs Regulations and General Directions 2016 (SI 2016/362), Diagram 878
- ACPO Road Policing — Safety Camera Guidance
- Road Traffic Regulation Act 1984, s.64
Frequently Asked Questions
- Does a missing camera warning sign automatically cancel my speeding ticket?
- No. There is no automatic cancellation. The missing sign is a factor courts and adjudicators weigh. For criminal speeding prosecutions, you would need to raise it at court. For civil traffic contraventions, raise it in formal representations and appeal.
- Does the camera warning sign apply to average speed cameras?
- Yes. Average speed camera zones must have warning signs at the zone entry. The SPECS system and similar average speed platforms require an overhead sign indicating the enforcement zone, in addition to the speed limit signs.
- Can a council put the warning sign anywhere?
- No. TSRGD 2016 and the DfT camera guidance specify placement. The sign must be placed so that a driver approaching at the relevant speed limit has sufficient time to see it and adjust. Placement deviating significantly from the guidance is a potential defect.
Related
- missing-camera-warning
- tsrgd-2016
- TSRGD (Traffic Signs Regulations and General Directions)
- NIP (Notice of Intended Prosecution)
- road-traffic-offenders-act-1988-s-1
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