The Italian Customs confirmed today that the UK will still be part of the EU’s Customs and Tax (VAT and Excise) territory after 31 January 2020. Indeed the UK will be treated as a third country for EU trade only after 31 December 2020 with substantial consequences for UK businesses operating in Italy also from VAT perspective (need of VAT Rep, VAT refunds, triangulation simplifications, etc).
Source Italian Customs authorities
