The location of your domicile is important if you are UK resident and not domiciled in the UK and have overseas income.
If you are both a resident in the UK and your domicile is the UK, then you pay UK tax on all your worldwide income and gains as they arise. However, if you are UK resident and not domiciled in the UK, you also pay UK tax on your UK sourced income and gains on the arising basis.
However, you also have the option of choosing to pay UK tax on your foreign income and foreign gains either as they arise or on the remittance basis (i.e. you are taxed on the funds only when you bring them into the UK). If you wish to be taxed on a remittance basis, you need to opt for this with HMRC and there may be a charge.