Mr Harris has become Ireland’s youngest ever Taoiseach after TDs backed his nomination.

Mrs Long said: “I want to congratulate Simon Harris on becoming Taoiseach and wish him all the best in his new role.

“The tenure of his predecessor Leo Varadkar saw a close and productive working relationship further progressed between Northern Ireland and the Republic, and I am confident Mr Harris will continue to nurture this positive partnership between the North and South.

“In the coming days and weeks ahead, we will continue to work together with those across the political spectrum with the aim of strengthening co-operation across the island of Ireland, and I look forward to working with Mr Harris as part of that.”