We’ve had help answering this question from our friends at the Institute for Government.
If we leave the EU in March 2019 with no deal the UK would be able to negotiate and put in place new trade deals as soon as we had agreed them. The immediate priority, though, would be to ‘carry over’ the trade deals we have now as an EU member and continue to trade with other countries under those terms.
If the UK does finalise a withdrawal agreement with the EU before the end of March 2019 then we’ll enter the transition period. During this time we can negotiate new trade deals, but the UK can’t implement them until that period ends (in December 2020, unless the transition period is extended).
If the withdrawal agreement is passed, but no deal on the future relationship with the EU is reached during the transition period, the UK enters the backstop to ensure that the border between Northern Ireland and Ireland remains open as it is today. During that time the UK will still be able to implement trade deals, although its ability to have a trade policy that is independent of the EU will be limited.
A key part of the backstop is the ‘single customs territory’ between the UK and EU—that means that the UK and EU must have the same tariffs for other countries.
The backstop also commits Northern Ireland to staying aligned to some of extra rules of the single market that are important for avoiding a border on the island of Ireland. So if the UK were to sign an agreement with another country and the rest of the UK diverged from EU rules, it could result in more substantial checks on goods moving between Northern Ireland and the rest of the UK.
We’ve written more about the backstop here.
This article is part of our Ask Full Fact series on Brexit, answering your questions about Brexit and the latest negotiations between the UK and the EU.
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