In the almost 12 years that Justin Welby has been archbishop of Canterbury, the Church of England has both cemented its place at the heart of the establishment and become less and less relevant to the lives of most citizens.

Welby has buried a queen, crowned a king and married a prince. He has offered spiritual counsel to six prime ministers and debated issues of national importance in the House of Lords. He has addressed the nation regularly via the BBC, with Christmas, new year and Easter messages and occasional Thought for the Day broadcasts.

Whether the nation has paid much attention is a different matter. During Welby’s tenure as the most senior cleric in the established church of the country, regular attendances at Church of England services have continued to decline, despite repeated evangelising drives.

In 2012, just before Welby’s appointment, average weekly attendance was more than a million people. By 2023, the figure had fallen to 685,000. The 2021 census showed that less than half the population of England and Wales described themselves as Christian.

Welby, the 105th archbishop of Canterbury, succeeded Rowan Williams, a cerebral figure and eloquent preacher who was ground down by internal conflict in the church. With a background in the oil industry, the expectation was that Welby would be the C of E’s CEO as much as its spiritual leader.

One of his first successes was to drive legislation to allow female bishops through the C of E’s ruling body, the General Synod, after years of bitter argument. The first, Libby Lane, was consecrated the following year. Now there are more than two dozen female bishops, and it is possible that the 106th archbishop of Canterbury could be the first woman to lead the church.

The tensions between traditionalists and progressives over female bishops did not go away, but became largely focused on another hot button issue: sexuality and same-sex marriage. Welby worked hard to hold the C of E – and the global Anglican church – together amid painful and sometimes acrimonious debate. But inevitably his efforts have frustrated campaigners on both sides.

The C of E now allows clergy to hold services of blessing for newly married same-sex couples. To advocates of LGBTQ+ equality and inclusion, it is nowhere near enough; to conservatives, it is far too much. Some of the latter in the global church said they no longer recognised Welby as their leader, and some traditionalists in the C of E are intent on establishing a separate structure.

Equality campaigners are likely to continue to pressure the C of E to offer same-sex church weddings, and traditionalists will continue to resist. The next archbishop will find the issue still in his or her in-tray.

Welby became increasingly vocal about immigration, in particular the previous government’s proposals to send migrants to Rwanda. He described the policy as “immoral and cruel” and said the government was “leading the nation down a damaging path”. At least one Conservative MP lambasted him for preaching politics from the pulpit.

Welby apologised for the C of E’s “institutional racism”, and vowed to take action to address its “shameful past” complicity in the international slave trade.

The issue of abuse has been a constant throughout his tenure, with Welby issuing repeated apologies and acknowledgements of the “brokenness and failings of our church” in relation to sexual abuse. In the end, it was his own failings that led to his resignation.

On the face of it, Welby was born into privilege, but he had a difficult childhood with dysfunctional and alcoholic parents who separated when he was three. At the age of 60, he discovered that his biological father was not the “deeply abusive” man of his childhood, but Anthony Montague Browne, Churchill’s private secretary, with whom his mother had a drunken tryst days before her wedding.

Welby went to Eton, followed by Cambridge. He worked in the oil industry, sometimes in personal danger in areas of Nigeria, before giving up the corporate world to be ordained as an Anglican priest. He became bishop of Durham in 2011, and just over a year later was appointed archbishop of Canterbury.

He and his wife, Caroline, suffered unimaginable grief when their first child, Johanna, was killed in a car crash at the age of seven months. The couple have five more children, all of whom attended state schools. One son, Peter, is also an Anglican priest.

Welby, who will be 69 in January, has been open about his struggles with depression. On Radio 4’s Thought for the Day in 2019, he said he had sought help with the encouragement of his daughter, Katherine, who “helped me see that it wasn’t something to be ashamed of”. At the time of the broadcast, he was taking antidepressants daily.