Let me put your mind at rest - I've had personal experience with this.
Scenario: Me and a friend working on-site. We drove there in my car. I had to leave and go somewhere in my car. Half an hour later my friend asked to borrow my car and drove along a similar route to mine. A few days later I received a summons for speeding - giving the time, date and location.
My friend and I honestly (!!) couldn't remember who was driving at the time, so I wrote off explaining this, asking them for photographic evidence so we could identify the driver. They sent a copy of the photo and the following attached letter:
"Thank you for your recent communication in connection with the above notice.
As requested, I am enclosing photograph(s) which may assist you in identifying the driver of the vehicle at the time of the alleged offence, together with a further S172/request for information form. Please be advised that under Section 172 of the Road Traffic Act 1988 you have a legal duty to provide information which may lead to the identification of the driver.
If you are unable to provide this information, then the matter may be dealt with by the Magistrates' Court.
Yours faithfully .......... "
How unlucky can you get - the photograph was blurd and did not help one iota. I wrote back, returning the photo, explaining that the photo was too blurd and did not help.
Here's their reply:
"Thank you for your recent communication in connection with the above notice.
To date, you have not provided information which may lead to the identification of the driver of the above vehicle, as you are required to do so under S172 of the Road Traffic Act 1988. The Act states that you must exercise reasonable diligence in providing this information.
In this instance I understand the photograph(s) does not you in identifying the driver and instead of issuing a summons for you to appear before the Magistrates' Court, you are to treat this letter as a warning, on the understanding that this "defence" will not be accepted for any future offences.
Yours faithfully ....... "
Just for the record, it was in April 2010 (I kept the letters for posterity!!)
..... oh and 1 more thing ...... RESULT ...... 1-0 to me :)