"For the first time, the Driver and Vehicle Licensing Agency (DVLA) will issue a series of minimum physical and mental requirements motorists must fulfil including eyesight performance and reaction times. Tests, costing up to £80, will be offered to drivers to check whether they are fit to drive.
Anyone who chooses not to take the tests but declares themselves able to take to the roads will be committing a criminal offence if they fail to meet the established standards. The move is designed to weed out tens of thousands of motorists ? many of them elderly ? who use their cars while suffering from conditions which could make them a danger to themselves or others."
from here
I can see this one causing a lot of grief in years to come! I don't think that people I know who are deteriorating physically or mentally would be willing to accept that they are no longer fit to drive with the limitations on freedom that would bring.
I hope it is not enforced against those elderly people who only drive slowly to the local village shop, but that it is used against anyone who causes an accident or is found to be driving dangerously to ensure they are kept off the roads afterwards. Also that friends and family could report dangerous drivers - I have a family member with signs of dementia whose driving is increasingly erratic.