What treaties or (written) agreements would a hard border in Ireland breach, post-Brexit?



Would the hard border that would come up in a "no deal" Brexit (between the Republic of Ireland and Northern Ireland) be violating any binding agreements that the UK has signed? (And the same goes for question for the Republic of Ireland and/or the EU.) Or is it merely politically "unacceptable"?

There's video by the European Parliament which mentioned the Good Friday agreements and some EP resolution. But how binding are these with respect to actually mandating a non-hard border? And what do they actually prohibit or demand with respect to the border?


Posted 2018-07-20T03:00:29.410

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Related (as yet unanswered) question on [Law.SE]: What are the implication of the Good Friday Agreement for customs controls?

– phoog – 2018-07-20T03:46:04.240

@phoog: interesting, according to the discussion there, the GF agreement doesn't even mention the border controls. I have to wonder why would the EP video name-drop it then. – Fizz – 2018-07-20T04:02:11.690

3There are certainly points of the agreement that could be stretched by UK's withdrawal from the EU customs union. For example, it could be taken as a barrier to cooperation, which is an important concept in the agreement. The agreement also explicitly mentions its context as an agreement between two EU members, so that argues for renegotiation. But the agreement itself does not mandate an open border, or even mention the border explicitly, so it can't be binding in that regard. – phoog – 2018-07-20T16:28:31.397

Related: Why is having border controls in Ireland so problematic for Irish nationalists?

– Martin Schröder – 2018-07-20T22:08:12.320

@MartinSchröder: Not really. That question/answer pair comes down to: Why do Irish nationalists want an open border in Ireland? Because that's the best proxy they could get for a united Ireland (duh). Says almost nothing about any agreements, except name dropping GFA again. – Fizz – 2018-07-20T22:12:48.437


Strictly speaking the hard border might be politically necessary in case of a no-deal scenario. According to WTO rules, specifically the "Most Favored Nation" principle, should the UK keep the NI border open to trade, it would have to provide the same benefit to all other (WTO) nations. As for the Good Friday agreement it has already seen legal consequences in 2017 R (Miller) v Secretary of State for Exiting the European Union.

– armatita – 2018-07-31T15:05:24.580


There is likely no single law or treaty that a hard border would violate. In practice, it would challenge the devolution of governmental controls in Northern Ireland to the Northern Ireland Assembly and would potentially give cause for Northern Ireland fo attempt to leave the UK under the provisions of the Northern Ireland Act.

– aVeRTRAC – 2019-03-31T23:57:45.590



binding agreements that the UK has signed ... what do they actually prohibit or demand with respect to the border?

The Agreement

The Good Friday Agreement / Belfast Agreement / British-Irish Agreement of 1998 can be downloaded from either the Irish government website or the UK government website. It is titled "The Agreement"

It has two parts:

  • a multi-party agreement between political parties of Northern Ireland and
  • an international agreement between "the Government of the United Kingdom of Great Britain and Northern Ireland and "the Government of Ireland"

The UK obviously is a signatory to the second part, not the first. However the second part commits its signatories "to support, and where appropriate implement, the provisions of the Multi-Party Agreement"


This agreement discusses cross-border cooperation extensively but there is no explicit mention of border arrangements that I can find.

Much of the wording is open to interpretation and I would assume that the British-Irish Council would be the body that makes these interpretations.

For example, here is a section on security:

1. The participants note that the development of a peaceful environment on the basis of this agreement can and should mean a normalisation of security arrangements and practices.
2. The British Government will make progress towards the objective of as early a return as possible to normal security arrangements in Northern Ireland, consistent with the level of threat and with a published overall strategy, dealing with:
(i) the reduction of the numbers and role of the Armed Forces deployed in Northern Ireland to levels compatible with a normal peaceful society;
(ii) the removal of security installations;
(iii) the removal of emergency powers in Northern Ireland; and
(iv) other measures appropriate to and compatible with a normal peaceful society.

"normal security arrangements" would presumably include normal security arrangements at the border as well as those elsewhere.

Normal Borders

It can certainly be argued that border-arrangements between countries such as Norway and its EU neighbours are "normal".

If so, the presence of border posts for customs checks is not explicitly prevented by the agreement.

Politico.eu says:

one lesson from Norway is that even with the Nordic country's close ties to the bloc, border checks are necessary. Cars entering Norway at Ørje are stopped and drivers asked for their destination and the purpose of their visit. The border post was recently extended and rebuilt with new barriers and cameras. Staffing has also been increased.

We could also look at borders between, for example, Canada and the USA. Generally in the wider world it is "normal" for border posts to exist and for checks to be made at borders.

Political Declarations

The above is somewhat irrelevant because the Irish government, the British government and the EU have all stated that they have no intention of creating new infrastructure at the border.

These declarations are not treaties or signed agreements but they are a clear indication of current political intent.

UK Example

This government is committed to the Belfast Agreement and to do everything in our power to ensure no return to a hard border between Northern Ireland and Ireland.

ROI Example

In planning for the real possibility of a no deal Brexit, the Government’s approach will continue to be guided by the same priorities:
- ensuring the best possible outcome for trade and the economy
- the protection of the peace process and the Good Friday Agreement, including the principle of consent and there being no Hard Border

Hard border

So far as I know, this term is not defined in any international treaty and so is somewhat vague and ambiguous.

It is likely that people will interpret this differently. In most cases any kind of physical infrastructure at or near the border, perhaps even so little as a traffic camera, is likely to be regarded as constituting a hard border.

Other commentary

  • BBC

    What does the Good Friday Agreement say about a hard border?

    A lot less than you might think. The only place in which it alludes to infrastructure at the border is in the section on security.

    During the Troubles there were heavily fortified army barracks, police stations and watchtowers along the border. They were frequently attacked by Republican paramilitaries.

    Part of the peace deal involved the UK government agreeing to a process of removing those installations in what became known as "demilitarisation".

    The agreement states that "the development of a peaceful environment... can and should mean a normalisation of security arrangements and practices."

    The government committed to "as early a return as possible to normal security arrangements in Northern Ireland, consistent with the level of threat".

    That included "the removal of security installations". That is as far as the text goes.

    There is no explicit commitment to never harden the border, and there is nothing about customs posts or regulatory controls.

    (my emphasis)

None of the above means that any of the parties involved think it would be a good idea to have a hard border - whatever that may mean. So far as I know, all are committed to avoiding it and to supporting the spirit of the agreement and not just the letters of it.


Posted 2018-07-20T03:00:29.410

Reputation: 7 763

2The treaty mentions "removal of security installations" (legalese for no hard border) among other border-related topics. – Denis de Bernardy – 2019-04-03T13:51:04.253

1@DenisdeBernardy: I interpret that as referring to the heavily fortified police and British army posts and watchtowers which were in more places than the actual border. I believe that was more about demilitarisation than about removing customs checks for goods passing the border. I may be wrong of course, so any references that support the interpretation you suggest would be very welcome. – RedGrittyBrick – 2019-04-03T16:02:26.793

The BBC article has bit more to say, but again rather inconclusively: "Additionally, a section on economic issues states that, pending devolution, the British government should progress a regional development strategy that tackles "the problems of a divided society and social cohesion in urban, rural and border areas".

It could be argued that a hard border would conflict with the spirit of that part of the agreement but again there is no specific prohibition." – Fizz – 2019-09-03T11:19:48.127


For what it's worth, I'll add this bit, found via FullFact.org; a UK government position paper from Aug 2017 (position which presumably can change with the government):

  1. The invisible and open border between Northern Ireland and Ireland is, as the Irish Government has said, arguably “the most tangible symbol of the peace process”. [footnoted to: ‘Ireland and the negotiations on the UK’s withdrawal from the European Union: The Government’s Approach’, May 2017]. Customs controls were first introduced at the land border in 1923, shortly after the establishment of the Irish Free State. These controls, and the associated system of ‘approved roads’, were maintained to varying degrees until the the European Single Market was formally established in December 1992. In 1972 there was a chain of 17 HM Customs and Excise boundary posts at the major road crossing points along the Northern Ireland land border, with the other (over 200) crossings not approved for vehicular traffic. During the ‘Troubles’, customs posts were frequently the subject of bombing attacks. Border crossings and checkpoints were manned by a very substantial military and security presence, including a series of ‘watchtowers’ in border areas, and a number of border roads were blocked by the security forces adding to the disruption created by the approved road network. The Belfast (‘Good Friday’) Agreement included a specific commitment to “the removal of security installations”. [footnoted to: The Belfast (‘Good Friday’) Agreement 10 April 1998.] All military security installations and other infrastructure were removed following the Agreement and the border today is invisible and seamless across its 310 mile/500 km length. As the Irish Government has said, “the disappearance of physical border crossings and checkpoints is both a symbol of, and a dividend from, the success of the peace process”. [again footnoted to the 2017 Irish gov't position.]

So even if its loss is not a breach of any explicit treaty provision, it does seem that at least one of the governments considers the open border "the most tangible symbol" of the GFA peace process.


Posted 2018-07-20T03:00:29.410

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