alan.holmes wrote in :

Just as a demonstration that what I have written is correct, over the
past few years I have been accused of exceeding the speed limit nine
times, the first one I was stupid enough to pay, the second one was such
a farce that it bought home to me that these devices are not at all
accurate, so each one I asked to see the 'evidence five times I heard no
more, of the others it was not possible to assess the sped as one was a
laser gun, which have been recorded as being completely unreliable, one
occasion I was sent a single picture from a Gatso, clearly to hide the
fact that that was not correct, one went to court which again was a
complete farce, it was referred twice, on the second occasion I was
asked what questions I would ask the police, which I did not do, but
asked for it to be referred to a crown court, the CPS wrote to me saying
there was not enough evidence to secure a prosecution and I was offered
compensation, on one occasion I asked how was the thing calibrated, and
the answer was that it was 'serviced' once a year!

I'm late to the party with this reply, but I think it may be worth
making, so here goes...

In the days before I lost my driving license for 6 months, almost 10
years ago now, I used to exceed the speed limit regularly and
deliberately.

Whenever I was caught, whether by camera, laser or plain-clothes police
car, the speeds with which I was charged corresponded almost exactly with
those indicated by my speedometer.

Oh, and as I seemed to be temperamentally incapable of staying within
speed limits, once out on the "open" road, I never bothered to re-apply
for my driving license. I've had a lot of fun on my bike ever since, and
am much less poor than I would otherwise be.

--
Regards
Alex

http://www.badphorm.co.uk/