Angela Merkel, the German Chancellor, became the first world leader yesterday to condemn Pope Benedict XVI over his rehabilitation of an ultra-conservative British bishop who denies that Jews died in the Nazi Holocaust.

Ms Merkel called on the German Pope to reject publicly the views of Bishop Richard Williamson, who has denied that six million Jews were gassed in Nazi concentration camps. In a highly unusual rebuke to the Pope she said that she did not believe there had been “sufficient” clarification.

“This should not be allowed to pass without consequences,” Ms Merkel, daughter of a Lutheran pastor, said. “The Pope and the Vatican should clarify unambiguously that there can be no denial and that there must be positive relations with the Jewish community overall.”

Last week Pope Benedict expressed his “full and indisputable solidarity” with Jews and condemned denials of the Holocaust. Bishop Williamson had told Swedish television he believed that up to 300,000 Jews died in Nazi concentration camps, but that none were killed in gas chambers.

Cardinal Walter Kasper, head of the Pontifical Council for Christian Unity, which covers relations with Judaism, conceded that the episode had been mishandled. His remarks came after expressions of dismay by German bishops over a “loss of faith in the Pope” relating to the annulment of the excommunications of Bishop Williamson and three other ultra-traditionalist bishops.

Cardinal Kasper did not attack the Pope directly — an unthinkable act for a cardinal — but blamed the row on errors of management by the Vatican hierarchy and on a lack of communication inside the Vatican.

He said that there had been too little internal discussion of the Pope’s reinstatement of the arch-conservative followers of the late Archbishop Marcel Lefebvre, and a failure to foresee the row that followed. Cardinal Kasper told Vatican radio: “There have certainly been errors in the way the Curia \ handled this.” He added that the reinstatement of the four bishops was far from complete.

The followers of Marcel Lefebvre, who rejected the modernising reforms of the Second Vatican Council, were excommunicated after being ordained by him without authorisation from Rome, and formed the breakaway Society of St Pius X (SSPX). Cardinal Kasper said that the Pope had wanted to bring them back into the fold to reinforce the unity of the Church.

Leading Lefebvrists said this week that they still refused to accept Vatican II, which among other reforms condemned anti-Semitism and exonerated the Jews from blame for the Crucifixion of Christ. Bishop Williamson apologised to the Pope for the “anguish” that his views had caused, but did not retract them.

Mgr Gebhard Fürst, the Bishop of Rottenburg-Stuttgart, said that the rehabilitations were “a betrayal of trust, especially for our Jewish sisters and brothers”. Mgr Werner Thissen, the Archbishop of Hamburg, said that Pope Benedict XVI should not have lifted the excommunication until Bishop Williamson had recanted his “unspeakable” claims.