I have something of a vested interest in this for two reasons.
Firstly, my daughter's car was hit by an old lady's car as she mistook her brake and accelerator and wheel spun off a supermarket car park into the road writing off one vehicle and bouncing into my daughter's car with reparable damage, but major shock and upset.
Secondly my F-I-L is ninety next year, and refuses to give up driving, mainly due to pressure from my M-I-L who has never driven and has no idea of what is involved.
I seriously worry that he is an accident waiting to happen, his eyesight and reactions are not up to modern driving, and I think he actually knows this.
A government test would make the decisions for all these older drivers who may think they are still capable, but for whom an arbitrary test would make that judgement for them.