Let's see, now: 30,000,000 drivers. Retested every three years reduces the number to 10,000,000 drivers a year. 250 working days a year. Maximum five tests a day, so 8000 examiners required of a standard capable of testing the drivers. 8000 x £50,000 a year salary, pension, NIC, etc = £40,000,0000. Potential revenue from the tests at £100 a test = £1,000,000,000. Subtract typical annual costs of test centres and admin = £500,000,000. Subtract annual costs of training and re-testing the examiners = £8,000,000. Subtract ridiculous but typical annual salaries of 10 top executives = £200,000,000.

Yes, could be do-able. Could even make a profit. And would provide employment for all the police officers being made redundant now that the Olympics are over.