UK residents with foreign income or gains: double taxation relief: ‘Root income’ basis - practice
Tax credit relief should be allowed in all cases and for all years on the root income basis. Where relief is due strictly on the statutory income basis (see INTM161160, second paragraph), relief will be allowed on the root income basis unless the taxpayer specifically asks for the statutory income basis. Where the root income basis applies and the same foreign income is assessed once to UK tax and more than once to foreign tax, the total foreign tax is available for credit against the UK tax. Where the same foreign income is assessable to Income Tax for more than one UK year of assessment see INTM165100 onwards. Where the foreign income is not assessed for any UK year of assessment, no credit relief can be given
The summaries of agreements under the respective country entries will show specifically where the statutory income basis applies. For all other countries the root income basis will apply.