If you've not had to pay, then you've just gotten lucky.

Legally you should be paying VAT on any order over the value of £15, and import duty over £135. Not doing so knowingly is tax evasion.


Customs go through periods of clamping down, as it's well known china likes to under declare the value of goods.
If they suspect the value has been declared wrong, they will value the item at market value with VAT/tax accordingly, and if you want to appeal it, the onus is on you to prove they've valued it wrong.


Personally, I've got no issue paying VAT and import duty, but the courier fees are often a piss take. I paid a DHL invoice last night, which had to be paid before they will even deliver the item. IIRC the handling charge was about £25, then there was some kind of loss risk charge of £11 something, which was listed to cover their risk of people not paying for items after they'd been delivered. And yes, by prepaying, I still had to pay that fee. About half the total customs bill was for DHLs fees.