BP has ousted its chairman over what it called serious concerns related to “important governance standards, oversight and conduct.”

The departure was abrupt and unexpected, with Albert Manifold having been appointed to the position late last year.

“Albert has helped bring a welcome focus and pace to BP’s transformation," Amanda Blanc, senior independent director, said in a statement Tuesday. "However, the board has been surprised and disappointed to learn of governance oversight and conduct issues it deems unacceptable and has taken decisive action.”

BP's board was unanimous in the decision and Ian Tyler, a member of the board, was named interim chair, effective immediately. The company did not elaborate on Manifold's sudden departure.

BP, based in London, is a “supermajor,” one of the five largest oil production and exploration companies in the world when measured by revenue and profit.