SINN FÉIN, THE SDLP, Alliance and the Green Party have released a joint statement saying that Northern Ireland should stay in the single market and the customs union, and that there should be no hard border on the island of Ireland.

The four parties have varying stances on a number of issues, making their joint statement on a hard border and customs union membership significant. The four parties won 49 of the 90 Stormont seats in last year’s Assembly elections, according to RTÉ.

“This is critical to protecting investment, jobs, trade and the hard-won peace,” the parties said, in a joint statement today.

Although the UK government said that it wishes to avoid a hard border on the island of Ireland, British Prime Minister Theresa May has also said that it will leave the single market and the customs union – two statements which appear to contradict one another.

A number of suggestions have been made by the UK government to appease concerns – the main one being to use technology to customs-check vehicles and people in a non-intrusive way.

Another option, called “maximum facilitation” or “max fac” for short, would mean delaying the process of leaving the customs union until the technology to do so has been developed.

The EU and Irish government have expressed concern at this suggestion, saying that there is no technology that would deem infrastructure on the border unnecessary.

Members of Theresa May’s own government and party have also expressed reservations about the options that have so far been given.

Today, the statement signed by the leaders of four parties in Northern Ireland draws attention to the issue once more, during a week when the British government is working on suggestions for dealing with more complex aspects of the Brexit negotiations – including trade arrangements with the EU.

There has been no government in Northern Ireland for over a year now; the Stormont Assembly dissolved last year after the resignation of the late Martin McGuinness over the cash-for-ash scandal.

This has made Brexit negotiations even tougher for Northern Ireland as it has less representation of its region’s interests as the EU and UK hammer out a deal. The majority of Northern Ireland voted to remain in the EU in the referendum held in June 2016.

“The Joint Report of the EU and British negotiators published on 8 December last year reiterated its commitment to protecting the Good Friday Agreement, including the effective operation of the institutions and bodies of the Agreement,” the statement says.

“The Joint Report also affirmed that North South cooperation is a central part of the Good Friday Agreement and Prime Minister Theresa May committed to protecting and supporting continued North South and East West cooperation across the full range of frameworks of cooperation, including the operation of the North South bodies.

“All of the outstanding issues relating to the Withdrawal Agreement will be considered in relation to Northern Ireland/Ireland and the future relationship.

In relation to the protocol on ‘Ireland and Northern Ireland’, Theresa May has agreed that a backstop solution for the border will form part of the legal text of the Withdrawal Agreement, and that this backstop would apply, unless and until, another solution is found.

The political parties in the Northern Ireland Assembly wish to reaffirm our common position that we cannot withstand exclusion from the single market or customs union.

“That the protection of the Good Friday Agreement in all of its parts, including North/South and East/West co-operation is critical to maintaining relationships within, and between these islands.”