Sir Keir Starmer on Monday came under pressure from Sinn Fein to agree to a reunification vote in Northern Ireland as the new PM pressed on with a four-nation tour of the UK.
The Irish nationalists emerged from the General Election as Northern Ireland’s largest Westminster party, in terms of both seats and vote share.
Sinn Fein president Mary Lou McDonald urged Sir Keir to “embrace the right of Irish self-determination” following Labour’s landslide election win.
But Hilary Benn, newly appointed as Northern Ireland Secretary, said the prospect of a vote on Irish unity is “off into the distance”.
Irish Taoiseach Simon Harris concurred that a reunification referendum - which must be held on both sides of the border - was not a priority.
Sir Keir was visiting Belfast following a trip to Scotland on Sunday, and was also holding talks in Wales later on Monday.
He was expected on Tuesday to meet metro mayors in England before making a rapid-fire debut on the international stage when he attends a Nato summit in Washington.
The new PM said he was seeking an “immediate reset” of the relationship between Westminster and the devolved nations, insisting that Labour’s landslide victory had given it “a clear mandate to govern for all four corners of the United Kingdom”.
Starting his first full week in office, the new PM arrived at Stormont Castle early on Monday where he was met by Northern Ireland First Minister Michelle O’Neill of Sinn Fein and deputy First Minister Emma Little-Pengelly of the Democratic Unionist Party (DUP).
Ms O’Neill - dressed all in Irish green - congratulated Sir Keir on his success and they discussed upcoming parliamentary schedules in Westminster and Stormont, although Sinn Fein refuses to take its seven seats in the UK Parliament.
Sir Keir had already spoken by phone with the power-sharing Northern Irish leaders following his election success, and also had a conversation with the Irish premier before the pair are due to meet next week at Blenheim Palace when the PM will host a European summit set to include the French and German leaders.
The DUP was licking its wounds after slumping from eight Westminster seats to five.
Party leader Gavin Robinson said he would use his meeting at Stormont to press Sir Keir on public services in the province and trade with the European Union, but also stressed: “Now is a time for new beginnings.”
In Cardiff, Sir Keir was due to attend the Senedd and hold talks with Labour First Minister Vaughan Gething, who is resisting calls to resign after he lost a no-confidence vote last month.
