What is the Irish backstop?

Published: 15th Mar 2019

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. It would keep the UK very closely aligned to EU customs rules, with some regulatory differences between Northern Ireland and the rest of the UK.

The EU and UK have both said they don’t want the backstop to be used and will attempt to negotiate a future relationship that means the backstop won’t be necessary before it’s due to come into effect at the end of 2020.

The backstop arrangements were agreed between the UK government and EU in November 2018 as part of the draft withdrawal agreement. This agreement was rejected by parliament in January 2019.

In March 2019, the UK government and the EU agreed an additional “instrument” on the backstop, intended to address concerns that the UK could be made to remain in the backstop against its will. However the government’s legal advice says the UK could still be unable to exit the backstop if the future relationship negotiations fail.

The withdrawal agreement, plus the new “instrument” on the backstop, was rejected by parliament in March 2019.

If a withdrawal agreement isn’t approved at some point, this will likely lead to a “no deal” Brexit and 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 on 30 June 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.

Originally the plan was to leave on 29 March 2019. However on 14 March parliament voted that, in the event of the government’s draft withdrawal agreement passing parliament, the government should ask the EU for a short delay to Brexit, in order to give time for the necessary legislative processes.

The EU would have the final say on this delay but in all likelihood, if the deal was passed by parliament, the EU would approve this technical extension.

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.

How can the backstop be avoided?

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.

The withdrawal agreement says 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.

In March 2019 the UK government and the EU agreed a new “legal instrument” to accompany the withdrawal agreement.

The UK and EU are committed in the legal instrument to “working speedily” towards “alternative arrangements” to replace the backstop by the end of 2020.

In the opinion of the Attorney General (the government’s chief legal advisor), this instrument reduces the likelihood that the UK would be kept in the backstop against its will if the EU was blocking negotiations over the future relationship arrangements in bad faith.

However the legal advice also says that the instrument doesn’t reduce the likelihood that the UK could be kept in the backstop with no way to unilaterally exit it, if no bad faith on the EU’s part can be proved.

In practice this means the UK could not unilaterally leave the backstop in a scenario where an impasse had been reached between the UK and the EU, not through any demonstrable failure by either party, but simply because of “intractable differences.”

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), Northern Ireland (as part of the UK) would have different customs and regulatory standards to Ireland (as part of the EU). This means there could be a need for customs checks on goods to be introduced at the border, which could create a “hard border” with physical infrastructure, like cameras or guard posts. This would undermine the principle of North-South cooperation as set out in the Good Friday agreement.

In March, the UK government set out its plan for avoiding a hard border in Ireland in the case of no deal. It says it would introduce no new tariffs on goods crossing the border from Ireland into Northern Ireland, and no new checks or controls at the border itself (although some new customs requirements would be placed on a small number of goods, these would happen away from the border.

This is a unilateral measure set out by the UK government, meaning it only affects goods crossing from Ireland into Northern Ireland. We don’t know if the EU would apply the same measures for goods going in the other direction.

The government also emphasises that these measures would be temporary, and that it would continue to seek a permanent, negotiated solution to Irish border situation.

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".

Update 15 March 2019

This piece has been updated following parliamentary votes in the week of 11 March.

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.