CGT on foreign bank account where no money passes between that and the UK

[Matthew]

I have money in an overseas, non-stirling, foreign currency bank account. Let’s call the currency Franxs (Fr). Money is staying in the bank. Money is not travelling back & forth between that country’s bank and my UK bank. I make use of the money whenever I visit that country, which is frequently.

HMRC know of the account, but their website has nothing to help me with the following.

The bank is busy (with my money) buying and selling shares all the time. (It’s the only option.) They tell me what they’ve bought & sold. Let’s assume that 1000 shares were once bought for 600Fr (the 600Fr being in the foreign bank account, and not being transferred from UK £ via an exchange rate to Fr), and this year all 1000 are sold for 800Fr (the 800Fr still remaining in the foreign bank, and not being transferred from Fr via an exchange rate to the UK and into £). At no time has money travelled between that country and the UK.

How do I work out the capital gain/loss in £££ to complete my HMRC tax return?

[someone]

The election hasn't changed the answer you were given on Wednesday.

You convert the transactions to sterling and then calculate profit/loss for CGT (rather than calculate the profit/loss and then convert to sterling)