The writing is now on the wall for Archbishop of Canterbury Justin Welby after the Church of England's lead bishop on safeguarding refused to back him staying in post.

On BBC Radio 4's Sunday Programme on November 10, veteran presenter Edward Stourton asked Bishop Joanne Grenfell whether Archbishop Welby should resign in the wake of the Makin Review which exposed the C of E's cover-up of the John Smyth abuse scandal.

She said: "I really appreciate that the Archbishop has wholeheartedly apologised for what he could have and should have done differently in 2013.

"I also recognise his commitment over his tenure 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 we've seen over the last ten years."

Stourton noted that she had not given a straight 'Yes' or 'No' answer to the question whether Archbishop Welby should resign. She said: "I support the Archbishop's apology. I'm glad he's made it."

Archbishop Welby told Channel 4's Cathy Newman on November 7 when the Church of England published the Makin Review that he had considered resigning that very morning.

He told her: "I've given it a lot of thought. I've taken advice as recently as this morning from senior colleagues. And no, I'm not going to resign for this. If I'd known before 2013 or had grounds for suspicion, that would be a resigning matter then and now. But I didn't."

Was the lead bishop on safeguarding one of the 'senior colleagues' Welby consulted? Probably not. Though she has a very significant role in the C of E, she is not a diocesan bishop but rather the suffragan (area) Bishop of Stepney in London Diocese.

She is therefore not in Archbishop Welby's inner circle of advisers at his London residence Lambeth Palace. But that gives her an independence that makes her refusal to back him all the more potent.

Lambeth Palace has said the Archbishop does not "intend to resign" amid the growing calls for him to do so. But the politician-speak there would appear to be deliberate because what he intends not to do today can easily change.

The media calls for Archbishop Welby to resign are easier to withstand particularly from the right-wing press. Conservative MP Nick Timothy, who was Joint Chief of Staff to former Prime Minister Theresa May, made an articulate and informed case for Archbishop Welby's resignation in The Telegraph on November 11:

"Within the Church, Welby has presided over declining congregations, the closure of thousands of churches, and 'pastoral reorganisations', which critics worry will kill off the local parish. He launched a divisive Archbishops' Commission on Racial Justice, which last week accused some rural parishioners of racism. The Commission is chaired by Lord Boateng, a Labour peer, who has accused the Church of being rife with structural and systemic racism.

"If Welby believes the Church he has led for more than a decade is systemically racist, perhaps he should take responsibility for that. More likely, he, like other liberals, has gone along with ideological fashion, knowing he will not be among those who suffer the purges and punishments that follow his decisions.

"It was, perhaps, a similar carelessness that led to the personal and institutional failure to respond in 2013 to clear evidence of child abuse. Smyth, now dead, has escaped justice. But for the sake of his victims, and the Church itself, Welby should show the integrity he once said was missing in others – and resign."

But, articulate though this resignation call is, it can be dismissed among the higher echelons of the C of E as par-for-the-course Conservative criticism of Archbishop Welby. There is no love lost between him and the Conservative Party after he so vehemently opposed the previous government's Rwanda plan to deal with illegal immigration.

Bishop Grenfell, however, is among the up-and-coming 'progressive' bishops. It is significant that on November 11, the day after Bishop Grenfell's BBC interview, the Bishop of Newcastle, Helen-Ann Hartley, another leading revisionist, told the BBC that Archbishop Welby's position was "untenable".

Given the significance of Bishop Grenfell's role as the lead bishop on safeguarding, heading up the C of E's response after multiple abuse scandals, her studied refusal to support him means the high-level pressure is piling up on Archbishop Welby to go.

Julian Mann is a former Church of England vicar, now an evangelical journalist based in Lancashire.