I have 100,000 vested EMI share options from my employer, who are a UK company but publicly traded on the NASDAQ First North in Stockholm. The shares are currently trading at 20 SEK and were initially valued at 15 SEK a share.

If I exercise all 100,000 share options into my share trading account, will I have to pay any tax when I get them, or only when I sell them?

How much tax would I pay and on what?

Do I declare the tax in my next Self Assessment, or does it get reported some other way?

I've been told that they're covered under "Entrepreneur's Relief", but am unsure of how much Capital Gains Tax and/or Income Tax I'll have to pay, and when.

I'm currently in the Higher Tax bracket, if that's important.