You are asking a question that is quite complex, in general...

You are asking a question that is quite complex, in general terms whatever country you are a "tax resident" in , will want to tax your worldwide income (subject to double tax treaties) however the UK is a special case where they can have people resident there without having their tax domicile there, which means they are only taxed on their worldwide income, to the extent that they repatriate that income to the UK. (Have a relative in that situation) It is one reason the UK is such a nice home to the super rich.

However, it is complicated, you really want to shout an accountant lunch one day, and quietly pick their brains.