In tax terms, residence is the country where you spend the most time, whilst domicile is the country you’d describe as your permanent home, even if you don’t live there. Domicile is mostly determined by your family background (particularly your father), although the definition is complex.
UK resident and domiciled
If you’re resident and domiciled in the UK, you’ll pay UK tax on all your income, wherever you earn it, and on your gains. However, different tax rules will apply to your UK income and foreign income and gains. UK Inheritance tax will be due on all your worldwide estate.
Non-UK resident but domiciled in the UK
You’ll be taxed on your UK income and some UK gains, but not on your foreign income or gains. UK Inheritance tax will be due on all your worldwide estate.
Non-UK domicile but resident in the UK
You’ll be taxed on your UK income and gains, and on foreign income and gains if they’re remitted to the UK. But you can claim not to pay UK tax on your foreign income and gains if they’re remitted elsewhere. Inheritance tax will only be due on your UK estate.
Non-UK resident and not domiciled in the UK
You’ll be taxed on your UK income and some UK gains, but not on your foreign income or gains. UK Inheritance Tax will only be due on your UK estate.