I am not currently able to investigate the actual situation but I think your statement must be incorrect. I am unaware of the UK government having issued such an edict regarding an individual having a Swiss Franc denominated account. However, unlike in so many other countries, banks in the UK do not offer foreign currency accounts based in the UK proper, only in some of the tax havens such as the Channel Islands (I don't know the historical/doctrinal basis but I am as near certain as can be that this is not a restriction on the individual but it may apply to the banks themselves). On the other hand, there is definitely nothing to prevent anyone living in the UK from opening a S.Fr. account somewhere else, anywhere that offers such a thing, and UK subjects living outside the UK of course have full freedom to do anything they like. The only requirement is to declare any interest/gain to whichever tax authority you are answerable to. The most obvious location for keeping a S.Fr. account is in Switzerland itself, you could then simply transfer money (e.g. Sterling) to there and it would be converted by the bank into S.Fr. Note that there is absolutely no bank secrecy in Switzerland and any European and/or USA tax authority can see the details of the account - this in accordance with international agreements.