Originally Posted by
Andriyko
If it does not matter how you call it then call it what it is - Air Passenger Duty. And premium travel is not taxed - you get a discount if you travel in economy which you lose if you later choose to travel in a higher cabin. Losing a discount and being taxed for traveling in a premium class are not the same thing.
Semantics. Net effect: You upgrade, you get out your credit card, you pay. Whether it's a "discount removed" or an additional fee, the end result is the same.