Hi
If you are resident in the UK, the you must declare your 'world-wide' income and capital gains, in a self assessment tax return, using the arising basis.
This means that you would need to declare gains from your interactive broker account on a self assessment tax return, even if you do not bring the gains into the UK.
As you would be non domiciled in the UK, you have the option to claim the remittance basis on a self assessment tax return.
Please have a look a the guidance at RDR1 (
Residence, domicile and the remittance basis: RDR1).
Thank you