The Christian Social Union, the political ally of Angela Merkel, the German chancellor, in the state of Bavaria, announced sweeping leadership changes yesterday in a move to drag the party out of one of its deepest crises after the electoral rout it suffered at the weekend.

The worst regional election result in 54 years for the CSU, sister party to Ms Merkel's Christian Democratic Union, has cast doubts over the chancellor's re-election prospects next year since Bavaria has historically been a strong source of support for CDU candidates at national polls.