Driving without insurance isn't an arrestable offence, so the police can't shoot out and arrest them, however it IS an offence.
Offenders can get 6-8 points, upto £5,000 fine and possible suspension. (
http://www.lawontheweb.co.uk/roadlaw.htm)
Don't get me started on uninsured drivers

The best hope is that the ******* gets pulled over by a copper. He could well end up with a suspension for having no insurance, and if he drives again, on a suspended license, that IS an arrestable offence.
EDIT: Hang on, he didn't have a license? Hmmm. I guess they didn't come out because he was gone, but it is an arrestable offense, I am sure.