I think an amount of confusion has crept in.
Let me, as the original poster, clarify what I am talking about.
If a person (me) is domiciled outside the UK, but temporarily resident in the UK, they are not liable for UK income tax on salary payments, unless they are "remitted" into the UK.
Such a remittance can take the form of spending the money in the UK, importing goods into the UK, or transferring the money into a UK bank account.
Liability to income tax in the person's home country is a matter which I shall not consider here. Liability to tax on interest is also a minor detail.
Now if the person wants to have easy access to his money worldwide, and is paid in GBP, he might wish to hold it in an offshore sterling account, whence he could spend it outside the UK, or transfer it onwards into a UK-based account and at that time pay UK tax.
I believe all this to be above board, and am currently looking for suggestions as to banks who might provide such a service.
If I am barking up the wrong tree, please correct me.