[SAIM1130] Savings and investment income: foreign income
ITTOIA05/S368 charges savings and investment income arising to a UK resident whether or not it is from a UK source, and savings and investment income arising to a non-UK resident only if it is from a UK source. See SAIM1170 for more on the tax treatment of non-residents.
So a UK resident is chargeable under ITTOIA05/S369 on interest arising on a deposit account, debt security or similar asset, even if the asset is located abroad.
See also SAIM9090 on the meaning of UK source in the context of interest paid abroad.
See SAIM5210 on the taxation of foreign dividends.