couple of things to note matey....
was the copper in clear view....stealth policing is not allowed...it's meant to be a visible deterent
did he have a high-vis vest on
was there a camera warning sign within 100 yds of his camera
was the camera operators activity advertised on the cheshire camera partnership website...again, its meant to be a deterent
<a class="postlink" href="http://www.pepipoo.com/Hidden_speed_traps.htm" onclick="window.open(this.href);return false;" target="_blank">http://www.pepipoo.com/Hidden_speed_traps.htm</a>
Visibility of Police Officers Who Are Performing Speed Checks
ACPO Traffic Enforcement Guidelines are also not mentioned in the law, but they unambiguously state that traffic officers performing speed checks should do so from a position that's clearly visible to the public - take a look.
"31.2 The operator must be clearly visible to the public and the target vehicle throughout the check."
So, if you see a Traffic Officer hiding behind a bush or working from inside an unmarked transit van, why not stop and ask them if they realise that their conduct is breaching the ACPO guidelines - please don't forget to ask them for their name, number and the contact details of their Chief Constable so that you can write a letter of complaint about the officer's conduct.
To 'Corroborate The Police Officer's Personal Opinion'....
ACPO guidelines also clearly state that the officer should only use speed-measuring equipment to corroborate their prior personal opinion of excess speed - take a look at section 32.5.
"32.5 Operators should bear in mind that the device confirms and corroborates prior personal observations."
This means that the officer is not supposed to point the equipment indiscriminately at all of the passing traffic, in the hope of catching one of the vehicles "speeding". This also explains why a police officer's witness statement normally includes the words "I formed the opinion that the vehicle was exceeding the speed limit".