Shares in USD tax in GBP

[Ceebeeby]

I hold a small amount of dollars in a US brokerage account. They are generally the proceeds from
Sales which I have paid CGT on.

I recently sold some US shares with small gain $1.1k but I'm told we have to apply the fx to the purchase price and sale price and use the resulting GBP gain for UK tax calc purposes. The GBP gain is higher ie £1.4k. As all my transactions were done (bought and sold) using USD, I am effectively paying tax on an inflated value that I never received.

Is this correct? Can it be offset in any way?
Thanks
Cb

[pawncob]

Purchases and Sales are converted at rate on the day. Can result in a cuurency gain, but it's still a gain.