Kevin......
Similar ideas are currently being discussed with The association of chief Police officers, where "offenders" would be ticketed when spotted by traffic wardens, police officers, "hobby bobbies" or traffic officers, giving them 7 days to remedy the missing document (insurance, mot, or tax), unless the database shows the relevant missing thing has not been obtained (i.e the car has not been insured, or mot'd) a crushing order will be issued, and the offending vehicle recovered and crushed. You will be given no chance after the crushing order has been issued to remedy the situation, you will be required to remove all property from the vehicle and allow it to be lifted.
Discussions have reached a "rubber stamp" stage by the government, but the election and change of government have temporarily halted the further implementation of this until the current govt have debated it in parliament later this month.
I do not think there will be any objections to this bill, and therefore it is the belief of my company and myself that it may be "law" and in force by October, or December at the latest. However, the motoring press generally agree with it, but the AA and RAC are pressing for a more lienient stance, i.e the ability for the owner to be able to "stall" the crushing if it can be proved that the car is worthy of being kept and relicenced, and there is a monitary issue, therefore it will only be immobilized with a wheel clamp that will be taken off on the day of mot, or with production of valid insurance or tax.