“Is there a tolerance level these days?”
Although any speed above the speed limit can lead to prosecution, in England and Wales there has always been a tolerance below which action is not normally taken. In 2000 this was formally set, by the Association of Chief Police Officers, at 10%+2mph above the limit. In Scotland there is similar tolerance but the precise level has not been published. This tolerance was not to accommodate possible inaccuracies in vehicle speedometers (which, by law, must never under record but instead can over record by up to 10%). The tolerance was allowed to prevent frivolous challenges to the accuracy of measuring equipment. (If a driver defends a speeding allegation by challenging the accuracy of the measuring equipment the burden shifts to him to cast doubt on its accuracy. It is obviously more onerous to cast doubt that the measurement is more than 10% inaccurate than it is to show it is just 2 or 3% inaccurate).
During last summer it was hinted by Police Scotland that their (unpublished) tolerance level might be discontinued:
http://www.driving.co.uk/news/just-1mph-too-fast-and-youre-nicked-new-zero-tolerance-approach-to-speeding/
Some forces in England and Wales are considering following suit. Bedfordshire police announced that parts of the M1 may also be subject to “zero tolerance”:
www.telegraph.co.uk/news/uknews/crime/11975971/Motoriasts-face-zero-tolerance-approach-to-speeding-on-the-motorways.html
As far as I know neither force’s proposal has yet been implemented (my article suggests that the M1 scheme may be operational by April 2016). I am therefore most surprised, Vulcan, to hear that you were threatened with prosecution for doing 44 in a 40 limit and absolutely astounded to learn that action was taken against a driver doing 31mph in a 30 limit. I have never heard of anybody threatened with prosecution for such a small margin over the limit. Are you sure these were the speeds alleged by the police and not the speeds the drivers believed they were travelling at?
“…the Speed Nazis only have only 14 days to send the the NIP (notice of intended prosecution) to you - allowing for possible postal delays you are in the clear after about 16 days.”
Not, strictly speaking, correct. If the NIP is not served on the Registered Keeper (RK) by day 14 (with the day of the alleged offence being day zero) then a prosecution cannot be pursued – postal delays or not. The difficulty the RK has is that if the NIP is posted in time to arrive within 14 days it is deemed to have been served unless the RK can convince a court that it has not. So the onus is on him to prove a negative – always a bit difficult. But if he does convince a court that the NIP was not served in time the prosecution fails. This was addressed in the case of Gidden v Chief Constable of Humberside. In this case the particular issue was a late NIP delayed because of a postal strike. The court ruled in Mr Gidden’s favour:
http://www.bailii.org/ew/cases/EWHC/Admin/2009/2924.html
“ ..money for old rope!"
Er... yes Bernie. But the old rope (and the money raised) depends upon people breaking a fairly easy to understand law and – currently at least – by quite a margin.