I've just been reading about the recently introduced new powers for HMRC to question UK tax residents with unexplained assets (Unexplained Wealth Order, UWO):
"An individual who receives a UWO must explain how they obtained the asset in question. HMRC and the other relevant enforcement bodies can apply for such an order at the High Court.
In order to obtain one, the body must prove that there is a reasonable cause to believe the individual holds assets worth more than £50,000 (€56,860, $70,471), and there are grounds to suspect the individual’s known income would not explain the ownership of the property."
(My italics) So the onus is very much on the authorities i.e innocent until proven guilty; a bit different to Spain, where everybody with assets overseas worth more than 50k must declare them, whether there is any suggestion of them being unexplained or not. As a result, people such as Mariedav's acquaintances, and Kavanagh, end up being effectively criminalised by the system through no real fault of their own. It's wrong.