Or you do the "not normal" thing - which by weight of £'s is the normal thing to do by orders of magnitude - and pay tax on a remittance basis only. The choice is yours, pay tax or keep it offshore and dont pay tax.
You can also become non-resident by moving abroad for a short period of time, no need to do so permanently.
The introduction of the statutory Residence test changed that. If you spend over half the year in the UK, don't have a permanent home overseas as well as in the UK, or work here full time you are resident - and you have to declare all earnings.
Playing domicile and residence games isn't as easy as it used to be.
You can also become non-resident by moving abroad for a short period of time, no need to do so permanently.