The prospect of a united Ireland emerges as a republican leader takes office in Belfast
BELFAST, NORTHERN IRELAND - FEBRUARY 3: First Minister Michelle O'Neill speaks during proceedings of the Northern Ireland Assembly at Stormont on February 3, 2024 in Belfast, Northern Ireland.

LONDON — A referendum on Irish reunification could be in the cards within a decade, according to Northern Ireland's first-ever nationalist first minister, who took office at the weekend.

Sinn Fein's Michelle O'Neill was appointed as first minister on Saturday, the first Irish nationalist to hold the office since Northern Ireland was founded as a Protestant-majority state in 1921. The Democratic Unionist Party's Emma Little-Pengelly was appointed deputy first minister.

It came after the Northern Ireland Assembly, the country's devolved parliament, reconvened for the first time in two years on Saturday after the U.K. loyalist DUP reached a deal with the British government to end a boycott over post-Brexit trade arrangements.

The island to the west of England is divided in two; Northern Ireland is part of the U.K., whereas its neighbor, the Republic of Ireland, is an independent nation and a member of the European Union.

Until now, Northern Ireland's first minister has always come from a British unionist party, but Sinn Fein, which advocates for Northern Ireland to rejoin the Republic, won the most seats in the assembly for the first time in 2022.

The DUP, Northern Ireland's largest British unionist party, boycotted the assembly in February 2022 in protest over post-Brexit trade rules and refused to return for two years, leaving the country of 1.9 million people without a functioning administration. The deal that secured its return includes a contribution of more than £3 billion ($3.8 billion) from the British government for Northern Ireland's public services.

The power-sharing rules of the assembly, enshrined in the Good Friday Agreement — a landmark 1998 peace deal that brought an end to three decades of sectarian violence in Northern Ireland — mean that the executive, which runs the country, must include both unionist and nationalist representatives.