Leaving the EU will affect the UK’s trade with the rest of the world in a variety of ways.
If the UK leaves the EU without a deal beyond the Withdrawal Agreement, it will introduce a new tariff schedule. (See question on details of tariff schedules).
These tariffs would apply to imports from all countries, except for those where a trade deal is in place.
The UK currently participates in around 40 trade agreements negotiated by the EU with more than 70 countries, representing c11% of the UK’s total trade. All of these will legally cease to apply at 23:00 on 31 December 2020.
However, the UK is seeking to reproduce the effects of existing EU agreements for when they no longer apply. This will ensure continuity of trading arrangements for UK businesses. A list of agreements expected to take effect from 1 January 2021 can be found here. The agreements may contain minor changes to the original agreement, particularly in the area of rules of origin and may contain minor changes to duty rates.
Some agreements however will not be in place before the end of the transition period. In this case, trade with these countries would take place on World Trade Organization (WTO) terms using ‘Most Favoured Nation’ (MFN) tariffs. This may result in changes to duty rates.
Information on preferential and MFN rates can be accessed at the European Commission’s Market Access database.