The UK tax system implies to tax a person in the UK upon all their income wheresoever derived provided there is a connection with the country. A "connector" is essential because it would be impractical, unacceptable, contrary to international comity (and, in some places, unconstitutional) for the tax jurisdiction to attempt to tax a person who has no connection with that jurisdiction.
Residence is one of the factors that "connects" a taxable person to the tax jurisdiction. It usually triggers UK taxation of the resident’s UK and foreign income whereas non-residents only pay tax on their UK income. Therefore, the consequences of becoming a tax resident in the UK are significant.
There are special rules for UK tax residents whose permanent home (‘domicile’) is abroad. In this case, there is no need to pay UK tax on your foreign income or gains if both the following apply:
> They are less than £2,000 in the tax year
> You do not bring them into the UK, for example by transferring them to a UK bank account.