If no claim is made under section 842 in relation to unremittable income arising in a territory outside the United Kingdom, the amount of the income to be taken into account for income tax purposes is determined as follows.

If the currency in which the income is denominated has a generally recognised market value in the United Kingdom, the amount is determined by reference to that value.

In any other case, the amount is determined according to the official rate of exchange of the territory where the income arises.