Wales, Scotland & Northern Ireland challenge UK unity

The First Ministers of Scotland, Wales and Northern Ireland, sign a memorandum of understanding affirming the regions' right to leave the UK.

Sinn Fein President MARY LOU MCDONALD: "This, this is our means. This is our roadmap. This is the Good Friday Agreement. It's almost 30 years old. And this explicitly sets out, as a matter of international law, that we have the right, without interference or coercion as Irish people, to decide our constitutional future."

Discussions about a potential reunification of Ireland intensified amid Sinn Fein's electoral achievements in Northern Ireland.

The 1998 Belfast Agreement provides for Dublin potentially taking control of Northern Ireland if the majority of people in Northern Ireland and the Republic of Ireland so wish.

It also gave formal recognition to Northern Ireland's multiple identities, allowing residents to identify as British, Irish or both.

John Swinney, the First Minister of Scotland and Rhun ap Iorwerth the First Minister of Wales expressed optimism that new British Prime Minister Andy Burnham may be open to a fundamental redesign of the relationship between the UK's Celtic nations and Westminster.