UK residents with foreign income or gains: claims for double taxation relief against UK tax: extended time limits
The normal time limit for making a claim to credit (see INTM162560) is extended where credit which has been allowed is later found to be insufficient because there has been an adjustment of the tax payable either in the United Kingdom or the foreign country. Similarly, the normal time limit for making assessments is extended where credit which has been given is later found to be excessive because there has been an adjustment of the tax payable either in the United Kingdom or in the foreign country. Where this has happened, the time limit for making claims or assessments is extended to six years from the time when the adjustments are made.
These extended time limits only apply where credit has already been allowed on the amount of the income in question (for first claims see INTM162560) and where there has been an adjustment of the tax payable. Where, for example, a foreign country charges a United Kingdom resident to tax on income for the first time and such a charge is made outside the normal time limits, this is not regarded as an adjustment of the tax payable. Any case where this is disputed should be referred to the Offshore Personal Tax Team (part of Charity, Assets and Residence) in the case of individuals and to Business International, Foreign Profits Team in all other cases.
See INTM161320, fourth subparagraph onwards, in the context of transfer pricing adjustments.