On June 2, 1953, I, then a boy of eight in my Sunday best, gathered - like countless millions more - to watch the coronation of Queen Elizabeth II on a neighbour’s television set that had been bought for the occasion. It was the first time I had seen television - or a monarch - and the ceremony remains one of my most powerful childhood memories.

It would have seemed inconceivable then that one day I would be asking whether the 1,000-year-old institution of monarchy was on the point of fading away, having bored us - and itself - to death. And wondering whether a royal house that, almost half a century earlier, had thrown over its name, its nationality and its closest relations in the name of survival could manage to reinvent itself again.

The monarchy was in effect rebranded 90 years ago by the Queen’s grandfather George V to confront a double threat. In 1917 the February revolution overthrew the Russian autocracy and Nicholas II, George’s first cousin and spitting image. At home there were strikes, mutinies and political radicalisation. George and his advisers responded with a series of bold measures to shed old baggage and make new friends.

Most dramatically, he dumped centuries of German dynastic history, culture and family connections by renaming the royal family the “House of Windsor”. His German relatives were stripped of their British titles, and Tsar Nicholas II and his family were left to their grisly fate at the hands ofthe Bolsheviks. And those German relations who remained in Britain were given British-sounding names. The Battenbergs, for instance, became the Mountbattens - a name that Prince Philip later fought in vain for his wife to adopt.

The monarchy became committed to the ethos of public service, of which it saw itself as the apex and exemplar. Crucially it became a “family monarchy” with morality at its heart. And it was morality, in its vulgar sense of sexual behaviour, that was to carry it to both its peak and its depths.

In the 1990s, when the Prince Charles and Princess Diana fairy story became a nightmare ending in divorce, not only was the Waleses’ marriage dead; so too was the family monarchy, with the wildest rumours flying around - even that Diana was killed on the orders of Philip, a ludicrous assertion that has surfaced again at the inquest into her death.

Charles’s marriage to his long-term mistress and the real love of his life, Camilla Parker Bowles, broke every rule in the Windsor book. Both parties were divorced and both had been openly adulterous. Was it a betrayal of the fundamental principles of the family monarchy? Or a long overdue recognition of changing times and values?

If the monarchy - or at least the prince - had changed its spots, the Church of England hadn’t, and the wedding had to be a civil ceremony before a registrar. Whether the legislation setting up such ceremonies was properly available to members of the royal family is a moot point. Windsor Guildhall was the humblest location for a royal wedding since the clandestine marriage of Edward IV and Elizabeth Woodville in 1464.

But Charles’s second marriage is only a foretaste of the problems that will arise with his coronation and accession. Will it be possible for Charles to have a coronation at all? Is it even desirable? Might it not be better instead to have a civil inauguration and let church and crown go their separate ways?

For who any longer believes in the central message of the coronation? That - as symbolised by the fivefold anointing - the monarch is personally chosen and consecrated by God? The Queen does, of course. But for the rest of us it seems an absurd way to proceed at the beginning of the 21st century.

Charles’s civil inauguration would also be a recognition that the United Kingdom has become the royal republic of Britain. The Dutch have a civil inauguration in which the crown is not placed on the monarch’s head. Instead the monarch touches the crown and swears the oath. A similar ceremony might represent a new and welcome accommodation between the two great strands in British political life - the royal and the republican.

All of which forces us back to the great upheaval of 1917, when the crown, shorn of executive power, was left with two strings to its bow. As “the head of our morality” it was the guardian of the British way of life; and as the fount of the modernised honours system it was the patron and prime mover of public service and the voluntary sector. The latter area is one that Charles has successfully made his own and upon which he can build.

It was his great-great-grandfather Edward VII, during his 60-year stint as Prince of Wales, who began to develop the royal role as patron of good causes. The resemblances to Charles’s situation are striking. Edward was the 60-year-old heir to a revered female monarch, Victoria, who had sat on the throne for decades. Edward also had tense relations with his father and a radically different vision of monarchy from his parents.

And he had already begun to sketch it out as Prince of Wales. He and his wife Alexandra were assiduous in travelling the length and breadth of the country to open people’s parks and people’s palaces. These were the fruit of local self-help and municipal enterprise. In medical charities, however, Edward was proactive, using friends among the new plutocracy in the City to help finance the London hospital in the half-century before the National Health Service.

In that sense, Charles will be a reversion to type. Edward’s successors found themselves unable to develop his pioneering role, as the burgeoning welfare state began to marginalise voluntary works. But now the tide is turning. The arts and universities are slowly being weaned off state funding. Alternative forms of finance are being sought for schools. Even the NHS is being subject to covert privatisation. Most important of all, perhaps, the state has lost confidence in itself. State welfare is seen as part of the problem rather than the solution. Suddenly a much wider foreshore appears.

And in Charles we have, for the first time since Prince Albert in the 19th century, a royal patron who could occupy it. Charles’s good causes used to be greeted with mockery, but suddenly there’s a realisation that practically everything he has sponsored has become mainstream.

He recently rescued Dumfries House, a noble Georgian mansion that state-funded heritage bodies were unable to save for the nation until, at the 11th hour, Charles cut the Gordian knot. He did so by borrowing £20m. The sum will be paid off by the development of a model community on an adjacent estate - a Scottish version of Poundbury, the prince’s eco-village in Dorset.

Only Charles could have done it. For only he has the necessary combination of social and economic power - and imagination - to pull it off. This intervention is described by the prince’s principal aide as a prime example of “charitable entrepreneurship”. At its

core are the prince’s charities, of which the Prince’s Trust is an outstanding example. New Labour and Tories alike strive to learn from it and emulate it.

For most of his life Prince Charles has looked a man out of his time. But now perhaps his time has come. Politicians are discredited and the machinery of state malfunctioning or broken. If the state can’t or won’t help, voluntary action, charitable giving and self-help are the only resort. But they need someone to inspire, direct and honour their efforts. No politician who attempted to do it would be taken seriously for a second. Maybe King Charles III could. It would be a new kingdom – of the mind, the spirit, culture and values – and would not be unworthy of a 1,000-year-old throne.

David Starkey’s Monarchy: The Windsors, will be broadcast on December 26 on Channel 4. His book Monarchy: The History of England & Her Rulers from the Tudors to the Windsors is published by Harper Perennial, £8.99