Muskett makes some very good points.

There must be a real danger that linking MH to certificate revocation would lead to people not getting help early on, with worse outcomes.

Most GPs are unable to make more than basic determinations of MH issues, before referring them on to specialists. But even specialists would be highly reluctant, except in the case of diagnosed violent psychopaths, to make any determination of risk to the public from most conditions. Indeed, someone who suffers bouts of anxiety which prevent them leaving the house or even getting out of bed is clearly very unlikely to pose a threat to the general public.

There is some US research that suggests that gun possession correlates with a higher risk of successful suicide attempts, which gets reported as “having a gun increases your risk of suicide”. When you dig into it, it’s much less clear-cut. Do Americans more prone to violence, including self-harm, have a greater likelihood of owning weapons in the first place, given their ready availability? Are there cultural factors around choice of method?

Finally, although some people do just “snap”, the vast majority of those who pose a serious threat to others have prior patterns of violent or other aberrant behaviour.