Cape Town — Archbishop Pius Ncube of Bulawayo, the fierce critic of the Mugabe government who faces court action over an allegation that he had an affair with a married woman, has resigned his post.

The Vatican Press Office announced today that Pope Benedict had accepted the archbishop's resignation, given under a canon of church law which covers cases where a bishop, through illness or another "grave reason," becomes "unsuited" to fill his office.

The announcement was made in a one-line posting on the Holy See Press Office's website.

The Catholic archbishop of Bulawayo is perhaps President Robert Mugabe's most vehement critic. He has described Mugabe's rule as "brutal" and "autocratic." He once called for the invasion of Zimbabwe and has suggested that "We are all praying that the Lord will take Mugabe away soon."

In July this year, he was subjected to what is widely believed to have been a sting operation co-ordinated by government intelligence agents, in which he was allegedly photographed with a woman.

Journalists accompanied the deputy sheriff of Bulawayo when he served court papers on Archbishop Ncube in an adultery case brought against him by the woman's husband, and Zimbabwe's state-controlled media gave the case substantial coverage.

Mugabe had revealed advance knowledge of the claims shortly before they were publicised.

Earlier this year, responding to a pastoral letter from Catholic bishops which criticised the government in unprecedentedly harsh language, Mugabe accused the bishops of deciding to "turn political."

He added: "And once they turn political, we regard them as no longer being spiritual and our relations with them would be conducted as if we are dealing with political entities, and this is quite a dangerous path they have chosen for themselves."

Ncube, a priest for 34 years, had served as the Catholic archbishop of Bulawayo, Zimbabwe's second city, for nearly 10 years.