Hi Katie R
As advised, if UK tax resident and domicile, you need to declare your worldwide income in the UK -
Tax on foreign income.
If you are UK resident and not domiciled, then by default your have to declare your world-wide income and gains; however, you have the option to use the remittance basis instead, where you only declare all UK income and gains and only that overseas income and gains, remitted to the UK.
Have a look at RDR section 9, as the remittance basis is not always cost effective:
Guidance note for residence, domicile and the remittance basis: RDR1
Thank you