On 9th of June, the Salvadoran Congress voted 62 out of 84 votes in favour of making bitcoin legal tender in the country, does this change the tax treatment of bitcoin in the UK?
For individuals, I understand that capital gains tax is still charged on any foreign currency held outside of a foreign bank account (unless the currency is held for a holiday). The treatment for individuals is therefore likely to remain unchanged, unless presumedly it is posisble to store your bitcoin in an El Salvaorian bank account.
For companies, HMRC have rejected the loan relationship rules as being applicable to bitcoin as it does not accept that bitcoin is money. Foreign exchange gains and losses, however, are treated under the loan relationship rules. Exchange gains and losses are defined by CTA09/S475 whcih states that they are profits/losses derived from currency flcutations against the pound. There does not appear to be a more specific definition of "currency" and therefore presumedly it means any legal tender of a country. It would therefore appear (or could be argued) that the loan relationship rules would now apply to bitcoin.
The intangible fixed asset regime may apply to some companies who carry out activities with cryptocurrency, but does not apply to monetary assets as defined by accounting standards. FRS102 doesn't define cash beyond "Cash on hand and demand deposits" and therefore presumedly it also means any legal tender of a country. It would therefore appear (or could be argued) that the IFA rules would no longer apply to bitcoin.
I don't know if gold is still legal tender in any country, and whether this would shed any light on whether bitcoin's tax treatment may now change.