LONDON (AP) — The leader of Northern Ireland’s largest unionist party has stepped down from the top job after being charged with allegations of a historic nature, the party said in a statement on Friday.

Jeffrey Donaldson left his post with immediate effect pending the outcome of the judicial process, the Democratic Unionist Party said. In accordance with the party rules, it has suspended him from membership.

Gavin Robinson, the member of Parliament for Belfast East, was named interim party leader.

The unexpected announcement came after Donaldson opted to have the party return to power-sharing in Northern Ireland with the Irish nationalist party Sinn Fein, following a two-year boycott of the political institutions following controversy over Brexit trading arrangements.

The DUP agreed to return to the center of power in Stormont following a series of assurances around Northern Ireland’s constitutional position within the United Kingdom.

Donaldson has been a member of Parliament since 1997 and was initially a member of the smaller Ulster Unionist Party. He joined the DUP in 2004.