The high court in Belfast has dismissed claims that a no-deal Brexit and the imposition of a hard border would damage the Northern Ireland peace process.
Lord Justice Bernard McCloskey said the applications were a matter of politics and that was not an area in which courts should intervene.
His decision follows the reasoning of the high court in London, which concluded that Boris Johnson’s advice to the Queen to prorogue parliament for five weeks was lawful. By contrast the Scottish appeal court on Wednesday ruled that the prime minister acted illegally in proroguing parliament in order to stifle debate in the Commons.
Delivering the judgment, McCloskey said: “Virtually all of the assembled evidence belongs to the world of politics, both national and supra-national.
“Within the world of politics, the well-recognised phenomena of claim and counter-claim, assertion and counter-assertion, allegation and denial, blow and counter-blow, alteration and modification of government policy, public statements, unpublished deliberations, posturing, strategy and tactics are the very essence of what is both countenanced and permitted in a democratic society.”
The judge did not deal directly with prorogation since he said it had been been the “centrepiece” of the English and Scottish cases.
The Belfast hearing, involving three cases, turned on different legal issues to those heard in London and Edinburgh.
Lawyers for the applicants in Belfast argued that by creating a hard border on the island of Ireland, a no-deal Brexit on 31 Octoberwould undermine the Good Friday agreement and other agreements that underpin cross-border cooperation between the UK and Ireland.
One of the applicants was a high-profile victims’ campaigner, Raymond McCord, whose son was murdered by loyalist paramilitaries in 1997.
Another victims’ campaigner, Jamie Waring, brought a case. He was represented by the Belfast-based civil rights organisation the Committee on the Administration of Justice (CAJ).
Northern Ireland’s appeal court will hear appeals against the decision on Friday. The Northern Ireland cases will eventually reach the supreme court in London next week when claims from London, Edinburgh and Belfast will be joined together in a three-day hearing.
This article replaces an earlier version that incorrectly claimed the judge had ruled on prorogation.