As stated in “The UK’s Approach to the Northern Ireland Protocol” paper published in May, Great Britain and Northern Ireland form one customs territory. The Government will ensure that no tariffs will be paid on any goods that move and remain within the UK’s customs territory.
To ensure that trade flows freely, the Government will make full use of the provisions in the Protocol giving it powers to waive and/or reimburse tariffs on goods moving from Great Britain to Northern Ireland, even where they are classified as ‘at risk’ of entering the EU market. Only those goods ultimately entering Ireland or the rest of the EU, or at clear and substantial risk of doing so, will face tariffs.
This principle needs to be formalised with the EU within the Withdrawal Agreement Joint Committee.