Following evensong, Mr Welby symbolically laid down his bishop’s crozier, creating a vacancy at the head of the Church of England which is unlikely to be permanently filled until the autumn.
His low-key and downbeat departure leaves behind a church facing a deeply bleak midwinter.
Most obviously and most urgently, confidence in the church’s hierarchy over safeguarding issues is at rock bottom following the publication of the independent review into its handling of the case of John Smyth – a serial and sadistic abuser of children over decades.
Mr Welby’s decision to resign over the matter, given the review’s damning criticism of his failure to grip the scandal, was the right one.
But subsequent calls for the archbishop of York, Stephen Cottrell, to resign, over a separate abuse case, underline the need for root-and-branch reform of in-house safeguarding structures.
A report commissioned last year by Mr Welby and Mr Cottrell called for responsibility for safeguarding to be handed to independent bodies, funded by the church. That recommendation has been parked. If trust is to be restored, it should be swiftly acted upon.
More widely, England’s established church appears to stand at a crossroads, as pews continue to empty and more and more parishes struggle to make ends meet. Congregations have not returned to pre-Covid levels.
Over 3,500 churches have closed over the last decade.
The British social attitudes survey in 2018 found that only 1% of 18- to 24-year-olds identified as Church of England.
According to alarming recent research, as many as one in three serving members of clergy may be suffering from some form of depression, as they cope with severe financial and pastoral pressures.
The next archbishop of Canterbury would need to be a miracle worker to reverse the long‑term trend of secularisation which has shaped this stark landscape.
But there are changes of emphasis, style and direction that can assist a rapprochement between the Church of England and a country in which many view it as an anachronistic remnant of a different age.
The choice of a female archbishop would help convey a new sense of seriousness and urgency over safeguarding, and send the right kind of message in relation to wider issues of diversity. In fairness to Mr Welby, the presence of eligible candidates is the result of a sea change in attitudes which is one of the legacies of his time in Lambeth Palace.
Similarly, moving ahead with proposals for standalone same-sex blessing ceremonies – and eventually same-sex marriages – would allow the Church of England to gain a broader hearing in a public square where a basic social liberalism is the price of entry.
As the ceremonial head of the worldwide Anglican communion, Mr Welby, like his modern predecessors, felt a burden of responsibility for maintaining unity across churches in over 165 countries.
But the circumstances of his unprecedented resignation, and the overall crisis of direction in the modern C of E, will require his successor to have a rigorous domestic focus.
The Church of England, just about, remains an embedded presence in our national life.
Unless it adapts, that may be much less true a couple of generations from now.