Before I became a tax resident in the UK in June 2021, my former company in Hong Kong granted me some company share options with an exercise price of A. These share options were related to my previous employment in Hong Kong when I was a Hong Kong tax resident. I haven't exercised the share options since then. If I want to exercise the share options now and the market price (the company is listed on the Hong Kong Stock Exchange) is price B, do I need to pay any income tax on the difference between B and A (given B > A)? In the future, if I sell the shares at price C (given C > B > A), should I declare a capital gain on the difference between C and A?