The UK taxes its residents on their worldwide income and gains, so your ‘tax residence’ is critical in determining how much UK tax you must pay.
One of the critical factors in determining the scope of your UK tax liability is your ‘tax residency’. If you are a non-resident – i.e. you don’t live permanently in the UK – then you are typically liable to tax on your UK-sourced income only. Tax residency is self-assessed for each tax year. Your entitlement to UK income tax and capital gains tax allowances and exemptions is directly affected by your residency.