Sir Keir Starmer needs to indicate what circumstances are necessary for the calling of a referendum on Irish unification, the Sinn Fein leader has said.

Mary Lou McDonald, who is seeking to be taoiseach following the Irish general election on November 29, said a Sinn Fein-led government would take immediate steps to progress the party’s long-held goal of unifying the Republic of Ireland and Northern Ireland.

She previously said the border poll could be held by 2030.

Ms McDonald said Sinn Fein would dedicate a junior ministry role to unification under the Department of An Taoiseach.

She also said her party would propose to produce a green paper on the matter within 100 days of entering government, followed by the convening of a citizens assembly to provide space for “wider democratic” discussion of unification.

Head shot of Mary Lou McDonald looking up
Mary Lou McDonald was speaking on the campaign trail again at the Irish election later this month (PA)

Speaking to reporters on the election campaign trail in Dublin, Ms McDonald said: “Beyond that, the conversation needs to be had with the British Government, with Keir Starmer’s administration around this decade.

“The British Government needs to start now indicating for them what they believe is the tipping point at which they believe a referendum would be called.

“I’ve pursued this with them for a long time through many prime ministers, but I think it’s necessary that the person who is taoiseach would pursue that because, obviously, that brings it to a different level, and a different proposition.”

Under the terms of Good Friday Agreement of 1998, the UK Government is obliged to call a referendum in Northern Ireland if there is evidence of a shift in public opinion in favour of unity. In that event, there would be a simultaneous vote in the Republic of Ireland.

Earlier this year, Sir Keir said he was committed to the principles of the Good Friday Agreement. However, while in opposition, he said a referendum on Irish unification was “not even on the horizon”.