Jeremy Corbyn has rebuffed claims he will seek a united Ireland if he becomes prime minister during his first visit to Belfast since becoming the leader of the opposition.
The Labour leader said he would not seek a border poll unless there was an obvious demand for it during a speech in which he went out of his way to praise senior unionists such as Lord Trimble and the late Rev Ian Paisley.
He spoke out following reports on Thursday that unionists remain suspicious that Corbyn supports the unification of Ireland and retains sympathies for Sinn Féin and other republicans.
The Irish border issue is one of the most problematic aspects of the Brexit negotiations, with ministers trying to find a way of avoiding checks on the UK’s only land border with the EU.
Why is the Irish border a stumbling block for Brexit?
Inside the EU, both Ireland and Northern Ireland are part of the single market and customs union so share the same regulations and standards, allowing a soft or invisible border between the two.
Britain’s exit from the EU – taking Northern Ireland with it – risks a return to a hard or policed border. The only way to avoid this post-Brexit is for regulations on both sides to remain more or less the same in key areas including food, animal welfare, medicines and product safety.
Early drafts of the agreement Britain hoped to get signed off on Monday said there would be “no divergence” from EU rules that “support north-south cooperation”, later changed to “continued alignment” in a formulation that appeared to allow for subtle divergences.
But it raised new questions about who would oversee it and how disputes might be resolved. It was also clearly still a step too far for the DUP.
Addressing students and staff at Queen’s University, Corbyn was asked if he would advocate a poll on whether the border should continue to exist between Ireland and Northern Ireland.
He replied: “That would be a decision that could be made within the terms of the Good Friday agreement.
“If that is the wish, then clearly such a poll would happen. I’m not asking for it, I’m not advocating it. What I’m asking for is a return to the fullness of the Good Friday agreement which would open up the opportunities and possibilities for the future of Ireland as a whole.
“That is the point of the Good Friday agreement – not direct rule, not imposition of a political view from Westminster – but devolution of powers to Stormont here and of course the relationship with the Republic.
“It is quite clear that it’s there for a poll on both sides of the border, should that be something that is demanded,” he said.
Corbyn plans to visit the border on Friday. Research released by Queen’s University on Monday suggested that 53% of Catholics in Northern Ireland would be much more likely to want a united Ireland if there was a “hard exit” in which the UK left the customs union and the single market.
While the Northern Ireland secretary, Karen Bradley, has rejected calls for a border poll, unionists such as the MP Lady Sylvia Hermon have voiced concern that the UK’s decision to withdraw from the EU will “change everything” and will result in a border poll.
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Corbyn also claimed there was a majority in the House of Commons for Labour’s Brexit plans.
“Labour is clear there must be no border created in the Irish Sea,” he said.
‘Opposition to the idea of bringing back a hard border to this land isn’t just about avoiding paperwork or tariffs, important though that is, it’s about deep-rooted cultural and community ties. An open border is a symbol of peace, two communities living and working together after years of conflict, communities who no longer feel that their traditions are under threat.”
Corbyn had been invited to give a lecture in Belfast to mark 20 years since the signing of the Good Friday peace agreement. He urged Stormont leaders and the UK and Irish governments to renew efforts to restore power-sharing at crisis-hit institutions in Belfast, insisting peace cannot be taken for granted.
“As we stand here today in celebration of 20 years of peace, we must also recognise we are standing at a potential crossroads,” Corbyn said.
Northern Ireland has been without a properly functioning power-sharing government for more than 16 months due to a bitter stand-off between the two biggest parties, the DUP and Sinn Féin.
A row that broke out over a botched green energy scheme, and widened to encompass long-standing disputes such as the Irish language, gay marriage and Troubles legacy issues, shows no sign of resolution.