And what most people don't understand is that all we can do is pass the details of these people to their govts (the UK has actually started implementing our law/values extraterritorially, this btw is exceptionally unusual for non-US countries, with UWOs but, afaik, this only really applies if you do something stupid like buy UK property).

But generally: everyone has implemented US FACTA. All the old-style tax havens bar one or two have implemented (all the BOTs have). Laundering your money through London is an unbelievably bad idea, and has been for a long time (FATCA was the end, the US applied this extraterritorially so any bank that wanted to operate in the US had to comply globally).

What people get confused about is: it is perfectly legitimate to have money in any of the locations you mention (it helps you avoid exactly zero tax) but it isn't legitimate to not report those accounts to your tax authority (and all UK institutions, even in BOTs, are legally obliged to report the names/details of people involved in transactions...no question), and if that local tax authority chooses not to act on that information there is not much that can really be done (some places have said they won't comply i.e. Russia but most tax authorities aren't communicating tax information back to banks anyway).

Btw, software that flags suspicious transactions is used everywhere and that information is acted on (the FCA has regulators who check this, for what should be obvious reasons banks tend to be careful about who exactly does these investigations...if you work in this job, the FCA goes through your personal emails, they investigate your family, they investigate your friends, all your bank accounts are monitored...it isn't a joke). The issue is more often that the software doesn't work (i.e. a certain location has been flagged as high-risk but the software doesn't flag it)...and even then, firms are fined tens of millions on the spot if faults with their software are discovered. It is difficult to say that the UK is soft (particularly when most of the large scale tax loss is governments collaborating with large corporations to funnel profits).