Canadine & Ors v The Director of Public Prosecutions (DPP)

A minor, effectively invisible deviation in a prescribed traffic sign does not necessarily invalidate a speed restriction. The question is whether the sign complies with the applicable regulations, viewed in its proper physical context. A housing for illumination apparatus is distinct from the sign and is not a backing board merely because it creates a narrow visible rim. Even where there is technical non-compliance, the de minimis principle may apply where the deviation is immaterial and cannot mislead or misinform road users.

The claimants appealed by way of case stated from the decision of District Judge Snow at Marylebone Magistrates’ Court. They had been prosecuted for driving above the 20 mph limit on Tower Bridge. The district judge found that the terminal signs complied with diagram 670, although the illuminated signs were mounted in housings which created a small black lip visible only on close examination.

The appeal concerned whether that housing made the signs non-prescribed under section 64(1) of the Road Traffic Regulation Act 1984, so that the speed restriction could not be enforced.

1. The appeal was dismissed with costs. The signs on Tower Bridge complied with the relevant statutory and regulatory requirements.
2. Section 64(2) of the Road Traffic Regulation Act 1984, which treats illumination or its absence as part of the type or character of a sign, concerns the illuminated state of the sign. It does not make the housing containing illumination equipment part of the sign.
3. Direction 42 of the Traffic Signs Regulations and General Directions 2002 regulates the colour of the back of a sign, backing board and any container enclosing illumination apparatus. It does not make every visible part of an illumination housing a backing board. A backing board is a background against which the sign is displayed.
4. The housing was independent of the sign and created only a very narrow rim which was effectively invisible to motorists. It therefore did not alter the prescribed character of diagram 670.
5. Strict and complete compliance with regulations governing road signs remains the general rule, as recognised in Davies v Heatley [1971] RTR 145. That rule does not mean that every deviation inevitably invalidates a restriction. Following Sharples v Blackmore [1973] RTR 249 and Cotterill v Chapman [1984] RTR 73, an immaterial and very minor deviation may be disregarded under the de minimis principle.
6. Alternatively, even if the housing meant that the signs technically departed from the regulations, the deviation was so slight, and created no risk of misleading or misinforming road users, that it should be disregarded. The question referred by the magistrates’ court was answered accordingly.

• High Court (Administrative Court): District Judge Snow’s decision was upheld. The appeal by way of case stated was dismissed with costs assessed at £1,500.