Probably worth quoting directly.
I'll just leave this here without further comment.
Brexit
Unfortunately, we will not be able to send parcels to the UK from mid December 2020 onward. Quite apart from uncertainty surrounding the shipping cost, taxation etc. after that time, there is also a problem caused by the British government deciding to impose a unique taxation regime which will require every company in the world in every country in the world outside the UK which exports to the UK to apply and collect British taxes on behalf of the British government. For providing this service they intend to charge a fee to every company in the world in every country in the world which exports to the UK. Clearly this is ludicrous for one country, but imagine if every country in the world had the same idea. If every country decided to behave in the same way then we would have to pay 195 fees every year, keep up with the changes in taxation law for 195 different countries, keep accounts on behalf of 195 different countries and submit payments to 195 tax offices in 195 different countries, and jump through whatever hoops were required to prove that we were doing all of this honestly and without any error.
Therefore from mid December 2020 onward we ship to every country in the world... except the UK.