RDRM35510 - Remittance Basis: Miscellaneous: Timing of remittance - deemed income and gains
Deemed income or gains are not to be regarded as remitted before the time when they are treated as arising or accruing (ITA07/s809U).
Income or foreign chargeable gains that are remitted to the UK, before the income or gains to which they relate are treated as arising or accruing, will be treated as remitted to the UK at the time they arise or accrue and not before.
Income and foreign chargeable gains in this respect means the income or foreign chargeable gains and anything deriving from them.