The Archbishop of Canterbury is facing pressure to resign over a damning report into a barrister thought to have been the most prolific serial abuser to be associated with the Church of England.

A petition by some members of the General Synod – the church’s parliament – has gathered more than 1,500 signatures urging Justin Welby to stand down over his “failures” to alert authorities about John Smyth QC’s “abhorrent” abuse of children and young men.

The call has been strengthened by a bishop’s public statement saying Mr Welby should quit, describing the church as being “in danger of losing complete credibility” on safeguarding.

The Bishop of Newcastle, Helen-Ann Hartley, told the BBC: “I think that it’s very hard for the church as the national, the established church, to continue to have a moral voice in any way, shape or form in our nation when we cannot get our own house in order with regard to something as critically important, something that would be asked of any institution – let alone the church, which is meant to have the gospel of Jesus Christ looking out for the most vulnerable in our midst.

“We are in danger of losing complete credibility on that front.”

Of Mr Welby, she said: “I think, sadly, his position is untenable, so I think he should resign.”

I think that it's very hard for the church as the national, the established church, to continue to have a moral voice in any way, shape or form in our nation when we cannot get our own house in order

She said while his resignation is “not going to solve the problem”, it would be “a very clear indication that a line has been drawn, and that we must move towards independence of safeguarding”.

Mr Welby, speaking to Channel Four when the report was published, said he had been giving resignation “a lot of thought for actually quite a long time”.

But he added: “I have given it (resigning) a lot of thought and have taken advice as recently as this morning from senior colleagues, and, no, I am not going to resign.”

Following the petition’s launch, Mr Welby’s spokesman said he “reiterates his horror at the scale of John Smyth’s egregious abuse, as reflected in his public apology”, repeated that he does not intend to resign and said he “hopes the Makin Review supports the ongoing work of building a safer church here and around the world”.

Labour MP Marsha de Cordova, who represents the church in the Commons, said: “I recognise the Archbishop of Canterbury’s acknowledgement of and apology for his own failure to act with sufficient urgency in his response to learning about the abuse in 2013.

“This case is a stark reminder that there is much more work for the Church of England to do to ensure it provides safe, open and transparent spaces for everyone in society.”

Prime Minister Sir Keir Starmer declined to say whether he thought the archbishop should quit.

He told reporters: “That’s a matter really for the church rather than for me.”

The Makin review into Smyth’s abuse, published last week, concluded that he might have been brought to justice had the Archbishop of Canterbury formally reported it to police a decade ago.

Opportunities to establish whether (Smyth) continued to pose an abusive threat in South Africa were missed because of these inactions by senior church officers

Smyth died aged 75 in Cape Town in 2018 while under investigation by Hampshire Police, and so was “never bought to justice for the abuse”, the review said.

Across five decades in three different countries and involving as many as 130 boys and young men in the UK and Africa, Smyth is said to have subjected his victims to traumatic physical, sexual, psychological and spiritual attacks, permanently marking their lives.

The Archbishop said he had “no idea or suspicion of this abuse” before 2013 but acknowledged the review had found that after its wider exposure that year he had “personally failed to ensure” it was “energetically investigated”.

Mr Welby knew Smyth because of his attendance at Iwerne Christian camps in the 1970s, but the review said there was no evidence that he had “maintained any significant contact” with the barrister in later years.

It said while he knew him and “did have reason to have some concern about him”, this was not the same as suspecting he had committed severe abuses, and concluded it was “not possible to establish” whether Mr Welby knew of the severity of the abuses in the UK before 2013.

Given his role in allowing abuse to continue, we believe that his continuing as the Archbishop of Canterbury is no longer tenable. We must see change, for the sake of survivors, for the protection of the vulnerable, and for the good of the Church

The report said Smyth “could and should have been formally reported to the police in the UK, and to authorities in South Africa (church authorities and potentially the police) by church officers, including a diocesan bishop and Justin Welby in 2013″.

It said “had that been done, on the balance of probabilities” Smyth could have been brought to justice “at a much earlier point” than the Hampshire Police investigation in early 2017.

It added: “Opportunities to establish whether he continued to pose an abusive threat in South Africa were missed because of these inactions by senior church officers.”

The petition states: “Given his role in allowing abuse to continue, we believe that his continuing as the Archbishop of Canterbury is no longer tenable.

“We must see change, for the sake of survivors, for the protection of the vulnerable, and for the good of the Church—and we share this determination across our traditions.

“With sadness we do not think there is any alternative to his immediate resignation if the process of change and healing is to start now.”

I really appreciate that the Archbishop has wholeheartedly apologised for what he could’ve and should’ve done differently in 2013. I also recognise his commitment over the time of his tenure as Archbishop to really having tried to change safeguarding

Giles Fraser, vicar of St Anne’s in Kew, west London, described it as a “terrible situation”.

He told BBC Radio Four’s Today programme: There’s a petition going round now, which many people are signing and this is from all parts of the church.

“I’m afraid he’s really lost the confidence of his clergy, he’s lost the confidence of many of his bishops and his position is completely untenable.”

Dr Joanne Grenfell, the Church of England’s lead safeguarding bishop – speaking over the weekend, refused to say whether Mr Welby should resign.

She said she welcomed his apology “personally apologising for what he described as his failures after 2013 to really ensure energetically enough that this was followed through”.

Asked again if he should resign, she told Radio Four: “As I said, I really appreciate that the Archbishop has wholeheartedly apologised for what he could’ve and should’ve done differently in 2013. I also recognise his commitment over the time of his tenure as Archbishop to really having tried to change safeguarding.

“I think there’s still an awful lot to do but I do think that builds on some of the changes that we have seen over the last 10 years.”