Mr Corbyn used his trip to call for a customs union with the EU and insist that the Good Friday Agreement must not be put at risk.
But the intervention was overshadowed after he made clear that he still backs Irish unification – forcing him to promise that he would not push through a referendum on breaking up the UK if he becomes PM.
The DUP also claimed he had failed to respond to an invite to meet those who had been injured and lost relatives at the hands of Republican terrorists.
Meanwhile, one of Mr Corbyn’s own MPs launched a searing attack on his track record on Northern Ireland today – saying he had campaigned for an IRA ‘victory’.
Mr Corbyn insisted he was not ‘advocating’ the break-up of the UK as he made his first visit to Belfast since becoming leader today
In 1984, a decade before the first IRA ceasefire, he met with Sinn Fein leader Gerry Adams in London and, a year later, he opposed the Anglo-Irish Agreement saying it strengthened rather than weakened the border
In a speech at Queen’s University, Mr Corbyn insisted he was not ‘advocating’ the break-up of the UK.
Asked whether he would want a referendum on Irish unification if he became PM, Mr Corbyn said: ‘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 whole.’
Demanding the government keeps Britain in the EU customs union after Brexit, Mr Corbyn said: ‘Opposition to the idea of bringing back a hard border to this land isn’t just about avoiding paperwork or tariffs, 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.’
Unionists have long been suspicious of Mr Corbyn because of his Republican sympathies.
Labour MP accuses Jeremy Corbyn of wanting IRA ‘victory’ in Northern Ireland
Labour backbencher Ian Austin
A Labour MP launched a searing attack on Jeremy Corbyn’s track record on Northern Ireland today – accusing him of campaigning for an IRA ‘victory’.
In an article on the PoliticsHome site, Ian Austin condemned Mr Corbyn and shadow chancellor John McDonnell for having views on Northern Ireland that were ‘completely outside the mainstream of the Labour Party’.
‘It might be ancient history for lots of the party’s new young recruits, but lots of older people will never forget what they said about the IRA during a brutal war which saw bombs planted and people murdered in shopping centres, hotels and pubs,’ he wrote.
‘A few weeks after the IRA blew up the Grand Hotel in Brighton and murdered five people at the Tory party conference in 1984, Jeremy Corbyn invited two suspected IRA terrorists to the House of Commons. When the man respo