British outrage at the position of the European Union with regard to the Irish border, as expressed by the chief negotiator, Michel Barnier, is misplaced. In fact, the European Union is demonstrating a greater understanding of the complexities of the situation in Northern Ireland and the need to protect the Good Friday agreement than the UK government and advocates of Brexit more generally.

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The only viable interpretation of the EU-UK joint report to conclude phase I of the Brexit negotiations in December 2017 is that either the UK as a whole remains part of the single market and a customs union with the European Union, or that Northern Ireland as a region does so. Anything short of that will lead to a hard border on the island of Ireland. This would have implications for the Good Friday agreement, north-south cooperation and the all-island economy.

In Northern Ireland, we are encouraged that this is the approach being adopted by the EU – even if we are saddened by the UK government’s refusal to face the contradictions embodied in its own positions – and the implications of commitments it has already made.

In essence, there is a trilemma: the British government cannot say it is committed to avoiding a hard border, to leaving both the customs union and the single market, and also to ruling out special measures for Northern Ireland. Something has to give, and in fact, the UK government has already given a firm commitment in the joint report to avoiding that hard border.

The UK government is engaging in wishful thinking if it believes that a hard border can be avoided through either a far-reaching free trade agreement or through technological solutions. The former is not the same as a customs union, with a common external tariff, nor does it fully address all non-tariff barriers. These are likely to be most apparent in the agri-food sector, which is the most integrated industry on the island of Ireland.

Brexit has serious consequences for political stability and has placed the constitutional question back on the table

Technological solutions are both untried and insufficient to address the full spectrum of challenges around a border. It is only full regulatory alignment that in practice can avoid a border, and this is reinforced by the deep connectivity of all aspects of north-south activity in Ireland – and the EU’s commitment that the single market cannot be cherry-picked.

Furthermore, the notion that in the context of a hard Brexit or no-deal scenario, the UK can unilaterally forgo its responsibility to erect a border and simply pass the buck to the Irish government and the EU, flies in the face of international trade policy and the principle of non-discrimination.

The outworking of the government’s own economic analysis reinforces the catastrophic economic consequences of a hard Brexit or no-deal situation. In this regard, Northern Ireland is the most vulnerable part of the UK both politically and economically. Any hard border would have massive economic, political and security implications. Our economy is heavily integrated with both the rest of the UK and with the rest of the island of Ireland, as well as the wider European Union.

Politically, Northern Ireland can only work on the basis of sharing and interdependence. The whole ethos of the Good Friday agreement was about breaking down barriers and allowing people to lead their lives on a north-south and east-west access. Yet Brexit entails new divisions and borders. Already Brexit has serious consequences for political stability and has placed the constitutional question, which has largely been parked over the past 20 years, back on the table.

For the Alliance party and many in the Northern Ireland business community, the challenge is more than simply avoiding any harm that would arise from a hard border. Our economy has been held back by the legacy of division and violence, and significantly underperforms relative to other regions of the UK and the Republic of Ireland. A hard Brexit would compound this further.

An outcome in which Northern Ireland continued to participate in the single market would allow our region to fully engage in both the EU single market and the UK’s internal market. This would be achieved through Northern Ireland remaining in line with EU law and regulations. Operating to these higher standards should not compromise simultaneous engagement with the rules of the market in Great Britain. In this sense, Northern Ireland could be a bridge.

Crucially, this approach is also entirely consistent with Northern Ireland’s current constitutional position. Indeed, a satisfactory compromise around this type of approach could bring much needed political stability and cohesion to Northern Ireland.

• Naomi Long MLA is the leader of the Alliance party of Northern Ireland