In the UK this is called customs duty, or import duty.
You can read all about it straight from the horse's mouth here:
https://www.gov.uk/government/publi...tice-143-a-guide-for-international-post-users
In a nutshell you pay, for non-EU goods:
(i) VAT at the standard 20 per cent (calculated on the cost of the item/s and shipping and insurance costs);
(ii) customs duty as per the rate for that item (kitchen knife = 8.5 per cent / sharpening stone = no customs duty) (also calculated on the cost of the item/s and shipping and insurance costs); and
(iii) a Royal Mail/Parcel Force handling charge (£8 or £13.50 see
http://www.parcelforce.com/sites/default/files/Customs leaflet.pdf)
There's also a sliding scale...
Goods Value and Customs Charges applicable
£0.01 to £15 No customs, No Import VAT**
£15.01 to £135 No customs, Import VAT due
£135.01 and greater Customs duty due, but waived if the amount calculated due is less than £9, Import VAT due
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Disclaimer: I wrote this pre-Brexit, after which we can maybe look forward to import duties from everywhere.