A bonus seems to be of more benefit to the bloody taxman than it does to normal folk. Absolutely f-in ridiculous how much of the bonus amount is paid as tax.
20% - yeah that's completely out of order. Or are you one of those unfortunate people who gets made to pay 40%? Struggling to buy that new Porsche after the taxman's had his bite?
Maybe you'd like to explain why they shouldn't tax your bonus in the same way as any of your other earnings?

