> Are you sure?
Yes. And it is bullshit.
Let's say you were given 1,000 shares of MSFT, today, at $72.50 -- the total award is worth $72,500. However, they make you pay half of that as an option. Your 'gain' in that case is $36,350. This is then converted to some GBP value, and then you are assessed, immediately, on that amount of tax being owed to the HMRC. It's counted directly as income -- even though it has never been realised, etc. As for how the company claims this on their balance sheet, I have no clue -- but it wouldn't surprise me if it didn't matter at all because most business keep their money offshore anyway, right?
*That* is the part that is ironic -- Amazon is making shitloads of money in the UK, but they're claiming they're just giving away shares to the employeeees and that's why they're not paying as much. We're enriching your people! We promise! It's total shit.
Bonus points: You can contribute to retirement accounts here, IF you do not make over a certain amount of money. This is easy to predict if you're just looking at base wages. However, if you get paid in stock, and the stock goes up quite a lot, you could get really fucked as the UK retroactively reduces the amount you were allowed to put into retirement accounts over the year. It's something like every 2 GBP you earn over some limit you can put 1 GBP less into retirement -- and the starting pool is ~11k GBP.
Last I checked, nobody could predict stock prices -- so it's a total shit show for admittedly a minority of people (those making anywhere from 100k to 150k GBP/year). Still, one would think that the UK gov't would realize that ultra wealthy people do not give a shit about putting 11k into a retirement account that cannot be touched until they're 65 or whatever. Why even regulate it retroactively?
The US is much more sensible in this respect. You get the award, it's valued at something, when you sell it they do a simple transaction showing how much you gained and that's it. Done.