It should be mandatory that all health care practitioners, doctors, GP's, opticians etc., report to DVLA any patient/client whose ailments or health condition affect their ability to drive. DVLA then decides if to revoke or suspend someone's driving licence, or ask them to resit the driving test.
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Every year people are killed or injured on our roads by drivers not fit to drive due to the onset of health conditions which were not present when they first took their test. Currently the law requires drivers to self report/regulate. If health practitioners were forced to report people incapable of driving, whether temporary or not, this could save lives and also the NHS millions.