For a few serious driving offences (which normally result in a lot more than 3 points) points have to remain on a licence for 11 years. For all other offences points have to remain on a licence for 4 years:
http://www.direct.gov...fications/DG_10022425
Thanks you two. Its not too serious. Some sort of alien machine photographed the rear of my car at four in the morning.Then had the cheek to send me a letter to tell me what it had done.Just imagine a machine telling me I've got an "SP30" and I don't have a leg to stand on.