MOT automatic monitoring
Why not issue chipped stickers with an MOT certificate that can be placed on the inside of a windscreen? These could then be monitored by the latest generation of average speed cameras. Offending vehicles can then be flagged and removed from the road if not successfully tested in a 30 day period. This is a similar sytem to toll gate stickers used in other countries and would free up police resources.
Chip not required - data links exist
Using existing number-plate recognition technology and the existing MOT database police can already identify MOT evaders. No chip required. One advantage of a chip-inside, though, could be to match the chip with the number-plate.
Currently you need an MOT to get car tax so seeing a car with out of date or missing tax ( vehicle excise ) stamp is a further clue.