Free Traffic Legal Advice

Good Afternoon.

I've just received a NIP from Surrey Police for an offence of 57.3mph in a 50mph zone, by an automatic camera device.

This is obviously a very marginal offence as, using the 10% + 2mph rule the minimum speed you can get prosecuted for is 57.0mph.

I've gone onto their website and viewed the evidence, as well as the calibration certificate for the camera. However, the calibration certificate does not state the accuracy/measurement uncertainty of the equipment. Any given item of measuring equipment has a certain stated figure for accuracy/measurement uncertainty, as nothing can be infinitely accurate. If the measurement uncertainty of the device in question was, for example, +/- 0.5mph then in my eyes the prosecution isn't valid, as I may have been going only 56.8mph, for example.

Would it be prudent to request this information, and how should I go about doing this?

Thanks

So you 'admit' to 56.8mph in a 50mph limit?

I think you can see where this is heading...  (I wouldn't call 13% over the limit as 'marginal')

The very threshold you refer to is to avoid such 'marginal' arguments.

As noted above, a prosecution can succeed for anything over the limit but in reality would not be pursued if it was 1mph or 2mph - most devices may publish an accuracy as +/-1 mph but are actually more accurate than that.  Indeed, the cosine effect can actually under report true speed anyway.

You are not going to escape an allegation of 57.3mph on this basis.  (Indeed, it's unusual that the allegation is so accurate, it's usually whole mph only)

This is obviously a very marginal offence as, using the 10% + 2mph rule the minimum speed you can get prosecuted for is 57.0mph.

Hmmm. Interesting.

If you read all of the guidance (rather than just the bits which suit your purpose) you will find this:

5. Disposal Thresholds for Speeding Offences 
   
5.1 Thresholds for disposal options are included in this guidance so that police forces can be consistent in their approach when dealing with those committing speeding offences. 
 
5.2 While this is a transparent approach, it has also resulted in the creation of a pseudo speed limit with many drivers understanding that they are unlikely to face any enforcement action unless they are speeding well beyond the posted limit, 35mph in a 30mph limit or 68mph in a 60mph limit, for example.   
 
5.3 Nothing in this guidance restricts police forces from prosecuting for speeds falling below the thresholds.  [My emphasis] However, such decisions should be taken on a case-by-case basis with due regard to the individual circumstances of the offence and relevant signage and engineering in place at the time. 

Also included in the guidance is the rationale behind the thresholds:

https://library.college.police.uk/docs/NPCC/Speed-enforcement-disposal-guidance-2025.pdf

Would it be prudent to request this information,

No. The police are very unlikely to engage in correspondence and you already have more material than they are obliged to give you at this stage. The idea of a course or fixed penalty (which you will be offered) is that you accept the allegation as it stands. If you want to make a technical defence you will have to plead not guilty in court and show that the device cannot be relied upon to prove you were exceeding the speed limit. If you decide to do that, do let us know how it goes.

Do not forget that whatever you decide to do, you must respond to the request for driver’s details within the 28 days allowed let us know