Non-resident trusts: trustees’ chargeability: Income Tax - tax pool
TSEM3020 describes the ‘tax pool’ for UK resident trusts.
Tax paid by trustees while a trust is non-resident does not enter the tax pool. Tax goes into the pool only if it is tax paid at a time when the trustees are UK resident.
See TSEM3790 if income distributions are made to beneficiaries of non-resident trusts.