The post you are reporting:
To take post 7 a stage further, whilst all duties/taxes go to “the State”, they are collected for different reasons. The most common tax is VAT - essentially 20% on almost everything; this is collected as revenue/income for the State. Less common, in that it applies to a much narrower range of goods (booze, fags and the like), is Excise Duty; again, this is collected as revenue/income.
Then we get to Customs Duty, of which I daresay we’ll hear a lot more. This works on the principle that ‘foreigners produce things more cheaply than we do’ and is designed to increase the cost of their things, back up to the cost of our home-produced things. In other words, it’s protectionist and the duty rate varies according to how much protection is seen as being needed. If we don’t make that thing at all, or just as cheaply, then the rate is zero – but the goods still have to be declared (yes, even in a Customs union!). And finally: Anti-dumping Duty – this is “special measures” additional protection from foreigner suppliers who are getting production subsidies that enable them to really undercut us.