Once upon a time, news that the heir to the throne may decline his “supreme governorship” of the Church of England would have caused an earthquake. Bishops would have wept as theologians worried all night. Was the 1534 Reformation for nothing? As it is, the gossip extracted in the Daily Mail from the latest royal pot-boiler suggests that Prince William does not worship much and that he found his father’s coronation service hard to take. This is hardly worth a shrug. Perhaps the prince is just a normal human being. To anyone who takes the British monarchy with an ounce of seriousness, the ritual of coronation was a shocker. It presented Britain’s head of state as serving God rather than the British people. Priests splashed him secretly with holy oil like a Crusader king. Nothing indicated that King Charles was the embodiment of a democracy, more of an episcopal hierarchy. Less than half the population of England and Wales now calls itself Christian. Some 30 years ago, Charles first mooted his concern at being expected to represent a multicultural, multi-denominational society when showing such devotion to a particular sect. He wanted to be a “defender of faith” rather than “the” faith. This admirable ambition was hardly reflected in his coronation ceremony (though Jewish, Hindu, Sikh and Muslim representatives did greet him after the service). Hereditary monarchy is a dubious enough concept as it is without religious mumbo-jumbo. If the Prince of Wales wants his coronation to be at least passably modern – legitimised by public consent and acclamation – he should set to and plan for it now. At the very least, he might set it in a secular place such as the Westminster parliament. That much should be within his prerogative. Of course, none of this matters much. If the British people really enjoy this kind of medieval mysticism, who could complain? They seem to love it, as do tourists. The answer has traditionally been that monarchy should be built on firmer foundations, in case an unsuitable monarch arrives or a constitutional crisis ensues. From George III through Edward VIII to Princess Diana, the British crown has shown it can survive such upsets. But the suggestion that the monarch reigns only by the grace of God must risk one day seeming absurd and undignified. That the reign should also include supreme governorship over what is now a minority denomination, the Church of England, is surely more so. What this means for a king is one thing. What it means for the church is quite another. Its “establishment” – defended by the monarch under oath – gives it extraordinary status. It is the only British institution that is granted exclusive membership of parliament through its 26 bishops. The church has its own parliament, the General Synod, to which Westminster defers. Its wealth, overwhelmingly from property granted it by Norman and Tudor monarchs, is prodigious. As the Anglican religion loses support, its role in national ceremonies must also decline. The church’s membership as a proportion of the British population is down to single figures and declining. It would be wise both for the monarch and the church to acknowledge this and embrace disestablishment. Gladstone mooted the possibility of the “severance” of church and state in 1885 and it returned periodically to public debate throughout the 20th century. It was a measure of the church’s (dwindling) importance that disestablishment has never been adopted. The result is an ailing church saddled with a hierarchy of 108 bishops, a bureaucracy of 42 dioceses and thousands of medieval buildings, half of them effectively redundant, but which it is charged with maintaining. Only the great medieval cathedrals have shown some uplift, aided by their importance as oases of cultural activity across much of provincial England. What has become desperate is the fate of parish churches. In days past, they and their surrounding grounds were hubs of neighbourhood activity and welfare. A former archbishop, George Carey, once compared them to the NHS, a sort of spiritual A&E department situated in every village and town. Not any longer. Thousands now lie dark, empty and locked, year upon year, despite often occupying a prominent position at the centre of their community. The Church of England cannot begin to handle this awesome legacy. Other European countries have handed their historic buildings to local authorities – with taxing powers – to look after and repurpose. New uses simply must be found for England’s churches that restore some life to their communities, or they will eventually go the way of medieval castles and become piles of stone. Perhaps as he hands over the seals of office as supreme governor, King William might transfer his churches to the guardianship of the state. Simon Jenkins is a Guardian columnist