Once I become UK resident, can I avail myself of the remittance basis in respect of any income or gains arising on my cryptoassets?
HMRC's view on this is clear. If you are UK resident, they consider your cryptoassets are situated in the UK.
On that basis, you will incur capital gains tax on any capital gains you realise on them in the year they arise, without the benefit of the remittance basis.
Accordingly, the prudent approach will generally be for you to arrange before you become UK resident to own your cryptoassets via a non-UK company, or owned by a non-UK resident trust (subject to any restrictions that may apply to their transfer, such as if they were issued to you by your employer on the condition that you don't transfer the crypto without their consent). The company or trust (as the case may be) should not incur capital gains tax on any capital gains realised on the cryptoassets they own; and, with careful planning, it should be possible to rely on the remittance basis to extract these gains into your personal name without you incurring tax.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.