The Archbishop of Canterbury is being urged to quit over his failure to pursue a sadistic serial abuser who is believed to have abused about 130 boys.

Justin Welby is under growing pressure to resign after he failed to act when allegations about John Smyth QC, were brought to his attention. Smyth is believed to be the most prolific serial abuser to be associated with the Church of England.

Members of the Church of England’s ruling body, the General Synod, have launched a petition demanding that Justin Welby quits, “given his role in allowing abuse to continue”.

The Guardian reports: Welby had “lost the confidence of clergy,” Giles Fraser, a London vicar, told BBC Radio 4’s Today programme. “This needs to be our watershed moment in the church, where we look at the culture of deference, the way in which many of our senior leadership rally to defend each other.”

Welby said last week that he had considered resigning over his “shameful” decision not to act remorselessly to deal with reports of abuse by John Smyth, a powerful and charismatic barrister who died in 2018, when he was informed of them in 2013.

Lambeth Palace, the archbishop’s headquarters, said in a statement on Monday that Welby had “apologised profoundly both for his own failures and omissions, and for the wickedness, concealment and abuse by the church more widely” but “does not intend to resign”.

Pressure on Welby has been mounting since the publication last week of a damning report on the church’s cover-up of Smyth’s abuse in the UK in the late 1970s and early 1980s, and later in Zimbabwe and South Africa. About 130 boys are believed to have been victims.

The report by KeithMakin described the abuse as “prolific, brutal and horrific”. The C of E “knew at the highest level about the abuse” but its response was “wholly ineffective and amounted to a cover-up”.

The petition, signed by more than 1,500 people by Monday morning, said the report had “highlighted serious failures in the culture, structures, and leadership of the C of E … [and] the particular responsibility of Justin Welby, the archbishop of Canterbury, for these failures”.

Welby and other senior figures in the C of E were told of allegations that Smyth had abused dozens of boys who attended evangelical Christian holiday camps run by the Iwerne Trust, beating them viciously in his garden shed. Many of the boys were pupils at Winchester college, one the UK’s top public schools.

Welby had volunteered at the holiday camps in the late 1970s but has said he was unaware of the allegations at the time.

The Makin report said Welby was informed of the abuse allegations in 2013 but failed to take action, and that it was “unlikely” he would have been unaware of rumours surrounding Smyth when he was volunteering at the camps.

“[Welby] may not have known of the extreme seriousness of the abuse, but it is most probable that he would have had at least a level of knowledge that John Smyth was of some concern,” it said.

After Channel 4 News exposed Smyth’s abuse in 2017, Welby told the programme he had “no idea that there was anything as horrific as this going on … I had no suspicions at all”.

Calls for Welby to resign are being mainly driven by clergy who are frequent critics of the archbishop over his leadership of the C of E, though they may gather wider momentum over the coming days.

In any case, Welby is expected to announce his retirement in the coming weeks or months. Bishops in the C of E are required to stand down at the age of 70. Welby will hit that milestone in January 2026, but bishops generally give long notice of impending retirement as the appointment process is notoriously slow.

The statement on Monday from Lambeth Palace said: “The archbishop reiterates his horror at the scale of John Smyth’s egregious abuse, as reflected in his public apology. He has apologised profoundly both for his own failures and omissions, and for the wickedness, concealment and abuse by the church more widely.

“As he has said, he had no awareness or suspicion of the allegations before he was told in 2013 – and therefore having reflected, he does not intend to resign.”