It's a requirement to take the legal minimum (20 days), but most companies offer 25 or so so in practice you can usually carry over 5. I believe it's in order

It's a requirement to take the legal minimum (20 days), but most companies offer 25 or so so in practice you can usually carry over 5. I believe it's in order to nullify the ability for a company to apply alternative pressures to stop people taking their entitled holiday.