Delivering the judgment, Lord Justice Stephens said the decision to hold a border poll involves “political judgement” and an enduring policy would not accord with the requirement for flexibility.

Victims’ rights campaigner Raymond McCord brought the appeal after his argument was rejected by the High Court in 2018.

Mr McCord, represented by Belfast solicitor Ciaran O’Hare of McIvor Farrell Solicitors, argued that there is insufficient clarity or transparency in relation to the mechanism for directing a border poll under the Good Friday Agreement and the Northern Ireland Act 1998.

However, the Court of Appeal ruled that Northern Ireland Secretary has discretion to decide when to hold a border poll based on “the prevailing circumstances at any given time”.

Lord Justice Stephens added: “For instance a likely outcome may involve an evaluation as to whether there are other factors which will impact on voting intentions crossing traditional party or perceived religious lines and if so as to their impact.

“Instances of such factors are changes in social attitudes North and South, relative economic prosperity North and South, the taxation structures North and South, the outcome of Brexit and the nature of future trading relations between both parts of Ireland which in turn depends on any agreement between the United Kingdom and the European Union.”