The Prime Minister was in Belfast today where he met with Ulster leaders at Stormont in an attempt to kick-start negotiations on reviving the Northern Ireland Assembly.
Sinn Fein leader Mary Lou McDonald claimed “constitutional change is in the air” following the meeting, where the party advised Mr Johnson that it would demand a referendum if the UK crashed out of the EU - an event which could lead to the closure of the open border between the province and the Republic of Ireland.
The Scottish Government has already stated its desire to hold a second referendum on independence in the wake of Brexit.
Nicola Sturgeon pressed home the point when she met with Mr Johnson in Edinburgh on Monday, where the two leaders were said to have had a “robust” discussion on the issue.
But the DUP insisted today a referendum in Northern Ireland would not take place. Unionist leader Arlene Foster dined with the Tory leader in Belfast last night, where he “reiterated the fact that he would never be neutral on the Union”.
The meeting came amid ongoing negotiations aimed at renewing the Conservatives’ confidence and supply deal with the Unionist party which is keeping Mr Johnson’s minority UK Government in power.
The disagreement between London and the Republic of Ireland over the Ulster border has become the most contentious issue in Brexit negotiations with the EU.
Mr Johnson has repeatedly called for Ireland to scrap the border “backstop clause in a deal previously negotiated under Theresa May.
In an interview published today, Irish prime minister Leo Varadkar said: “Ireland isn’ going to be bullied on this issue and as a government and as a country, we are going to stick by our position.”