What is the Irish backstop?

Published: 17th Oct 2018

The “Irish backstop” is effectively an insurance policy in UK-EU Brexit negotiations. It’s meant to make sure that the Irish border remains open (as it is today) whatever the outcome of the UK and the EU’s future relationship negotiations.

The backstop arrangements were agreed between the UK government and EU in November 2018 as part of the draft withdrawal agreement. That draft agreement now needs to be approved by the UK Parliament.

If a withdrawal agreement isn’t signed before the end of March 2019 and we have a so-called “no deal” Brexit, there won’t be an Irish backstop arrangement.

We’ve put together a timeline of the Brexit process which briefly sums up the key issues and events.

What is the backstop?

If the draft withdrawal agreement is voted through, then in March 2019 the UK will leave the EU and enter a “transition period”, during which we’ll still be in the single market and customs union, and continue to trade with the EU as we do now.

During the transition period (which will last until, at the latest, December 2022), the government will negotiate our future relationship with the EU, including trade rules. Of particular focus is what will happen along the Irish border—the UK’s only land border with the EU.

But if those negotiations don’t lead to any agreement on the future relationship, the UK will continue to trade with the EU under the backstop arrangements following the end of the transition period. 

Under the backstop the whole of the UK enters a “single customs territory” with the EU. There are many parts to this but essentially there will be no tariffs on trade in goods between the UK and the EU and some (though not all) trade restrictions will be removed.

However, Northern Ireland alone will remain aligned to some extra rules of the EU’s single market to ensure the border between Northern Ireland and the Republic of Ireland will remain open as it is today. These separate regulations for Northern Ireland mean there would be some checks on goods entering Northern Ireland from the rest of the UK.

The UK has also committed to maintaining a “level playing field” in some areas with the EU by adopting measures to ensure it doesn’t get an unfair competitive advantage.

For example the UK has committed to keeping our state aid rules the same as the EU’s. State aid is where the public sector gives advantages (for example. tax breaks or money) to organisations (for example businesses) that could distort competition or affect trade between EU member countries. Generally, state aid is not allowed in the EU.

The withdrawal agreement does say that the UK and the EU could get rid of the backstop requirements, but only if both the UK and the EU agree it's not necessary to avoid a hard border in Ireland. In other words, the UK can’t opt out of the Irish backstop if the EU disagrees.

Many MPs have criticised the backstop since it was announced in November 2018. The two main reasons are that it will lead to different regulations for Northern Ireland compared with the rest of the UK (which some think threatens the integrity of the UK), and that the UK would not be able to leave the backstop without EU approval.

Why is there a backstop specifically for the Irish border?

The Irish border is singled out by both the UK and the EU for a backstop because of its importance for the Northern Irish peace process. The 1998 Good Friday Agreement was a key part of this peace process. One of the agreement’s three main points was creating the infrastructure for “North-South co-operation” between the Irish government and the newly-created Northern Irish Assembly.

This cross-border cooperation was a part of a strategy of “‘normalisation’ of relations between Protestant and Catholic communities within Northern Ireland and across the border”, according to the Institute for Government.

A key part of this ‘normalisation’ and cooperation process was the opening up of the border, which had previously been manned by British soldiers. Today, there are no checks at all on people or goods as they move either way between Northern Ireland and the Republic of Ireland, and trade across the border was worth £4 billion in 2016. The Irish government has said that the open border is “the most tangible symbol of the Peace Process”.

Both the UK and EU agree that, in negotiating a deal on the relationship after Brexit, keeping the border open and upholding the terms of the Good Friday Agreement is of critical importance. That’s why they’ve committed to the principle that, even if future trade negotiations   fail, there should be provisions in place to ensure that the border remains open, as it is today. That principle is the Irish backstop.

Why could Brexit affect the border?

The creation of an open border was, at least in part, made easier by the UK and Ireland both being EU members, and therefore part of the customs union and single market, which allows (among other things) the free movement of goods and people between EU countries.

As part of Brexit, the UK intends to leave both the single market and customs union. The terms of the Good Friday Agreement can be upheld without the UK being part of these two things, although customs and regulatory checks on goods will be necessary in some form (possibly away from the border).

Were the UK to leave the EU with “no deal” (in the event that the draft withdrawal agreement doesn’t get approved by parliament), there would likely be a “hard border” in Ireland which re-establishes physical infrastructure, like cameras or guard posts. This would undermine the principle of North-South cooperation as set out in the Good Friday agreement.

Update 28 November 2018

This piece has been updated following the publication of the draft withdrawal agreement.

Correction 9 January 2019

A previous version of this piece incorrectly stated critics of the Irish backstop have concerns "it will lead to different regulations for Northern Ireland compared with the rest of the EU", this should have read "rest of the UK".


We aim for our factchecks to be as accurate and up-to-date as possible. If you think we've made an error or missed some relevant information, please email team@fullfact.org.