LONDON — Senior people in the Church of England “colluded” over two decades with a bishop to help cover up his serial abuse of young men and boys, an independent review found on Thursday.

The unsparing report, titled “An Abuse of Faith,” centers on Peter Ball, the former bishop of Lewes and Gloucester, who was convicted in 2015 of misconduct in public office and of indecent assaults against 18 victims over a 15-year period from the late 1970s to the early 1990s. Now 85, Mr. Ball was released from prison in February after serving half his 32-month sentence.

Overseen by Dame Moira Gibb, a former social worker, the report shines an uncomfortable light at the highest echelons of the church. The report was commissioned by the archbishop of Canterbury, the Most Rev. Justin Welby, who called it “harrowing reading.”

Among the report’s most damning criticisms is its rebuke of the former archbishop of Canterbury, Lord Carey, now the honorary assistant bishop in the Diocese of Oxford. It accuses him of setting “the tone for the church’s response to Mr. Ball’s crimes” and enabling Mr. Ball’s declarations of innocence to be accepted, even as victims and members of the public came forward to expose abuse by the former bishop.