In his first visit to Northern Ireland as Labour leader, Jeremy Corbyn will say Labour will not support a Brexit deal that imposes a hard border between Northern Ireland and the Republic of Ireland.
In a speech at Queen’s University later, he’ll express support for a customs union between the EU and UK.
"Driven by the free-market fantasists within their ranks, the reckless Conservative approach to Brexit is a very real threat to jobs and living standards here in Northern Ireland and risks undermining and destabilising the co-operation and relative harmony of recent years," he’ss say.
"Labour will not support any Brexit deal that includes the return of a hard border to this island. But we are also clear there must be no border created in the Irish Sea either.
"That is why Labour has put forward a plan that would go a long way to solving this issue, a plan for which I believe there is a majority in Westminster. Let's not give up years of hard fought co-operation and stability for the pipe dream prize of race-to-the-bottom free trade deals with the likes of Donald Trump.
"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.”
Corbyn has also stated that he believes there is majority support for Irish unification in both Northern Ireland and the Republic of Ireland.
Pressed on Mr Corbyn's views on Irish reunification, his official spokesman said: "Over the years he has made his position clear that the majority of those people across the whole island of Ireland wanted to see that outcome, a united Ireland.
"But in the context of the Good Friday Agreement that can only come about through that constitutional process that is laid down in the agreement and Jeremy fully supports that."
Irish political editor Mick Fealty said Corbyn would be a “polarising figure”.
"Jeremy has always been well-socialised on the nationalist side, particularly on the more extreme end of republicanism.
“What’s been noticeable recently is that Sinn Fein, even representatives in Dublin who’ve been reluctant to be seen close to any British political figure, have been very warm in their association with Corbyn’s labour party," he said.
“In his earlier days as a backbench MP, he spent very little time amongst unionists and protestants during the conflict. I think that’s where he’s going to be least well-received and most distrusted - he’s quite a polarising figure in NI.”
He added that Corbyn was “absolutely right” in his assertion that people on both sides of the border favoured a united Ireland, but added there would have to be referendum for that to happen in keeping with the Good Friday agreement.
Listen to his conversation with Julia Hartley-Brewer above.