Gambling Winnings Tax at Unlicensed Casinos

I would like a confirmation regarding tax on winnings from gambling, specifically where the winnings come from a non-UK licensed online casino. I understand that in the UK, there is no tax on gambling winnings and this burden is instead covered by the gambling operators themselves. But, what happens if a player receives a substantial payout from an overseas online casino that is not UKGC licensed and does not contribute to the UK gambling operator's tax? For the sake of argument, let's say that a player wins £1,000,000 on an online slots game, would this income be liable for capital gains tax, or would the simple fact that the income came from gambling mean that it was un-taxed?

Hi Mark Funnell,
From a UK point of view, there would be no UK tax liability.
There may be tax payable in that other country.
Thank you.