Hi puzzled user,
Please have a look at the Insurance Policyholder Taxation Manual IPTM3700 onwards:
IPTM3700 - Foreign policies: differences in treatment
Foreign policies in most cases are not qualifying, which means the gain is taxable (IPTM3710).
Most foreign policies cannot in most cases be treated as though basic rate tax has been paid on any gains. (IPTM3720).
Where policies are denominated in a foreign currency, any gains should be worked out in that currency first, before being converted to pounds sterling.
The gain that the UK tax resident individual should be reported to HMRC in a Self Assessment Tax return, in the foreign section (SA106) in box 43, 44 and 46 of page F6.