As of 31 January 2021, the United Kingdom became a third country for VAT purposes, and the EU reverse charge rules for the supply of goods sent to/from the UK no longer applies. Companies instead should treat such transactions as exports or imports.
A triangular transaction is normally characterized by a number of things. The fact that a supplier (A) established in an EU country concludes sales transaction with a business customer (B) in another EU member state but the goods are directly delivered by the first supplier (A) to the last business customer (C) in a third EU country.
The simplification of the intra-community triangular transaction aims to prevent a VAT liability for the middle entrepreneur in the supply chain and the subsequent registration obligations. In order for the EU triangular simplification rules to apply, participants must be companies registered for VAT in different EU countries.