Christopher Wilson is the author of The Windsor Knot: Charles, Camilla and the Legacy of Diana, and a former columnist for The Times and The Sunday Telegraph

There is a major hurdle ahead which may yet do permanent damage to their relationship. In June, the Queen’s official birthday is celebrated by the Trooping the Colour ceremony, one of the most glittering jewels of British pageantry. It is customary for the royal family to gather on the Buckingham Palace balcony afterwards to acknowledge the crowds.

If Camilla – by then the second most senior royal lady after the Queen by virtue of her marriage – is absent from the balcony, we will know the worst. It will mean that there is no place for Camilla in the Queen’s immediate circle. Charles, who has allowed his heart to rule his head in the matter of Camilla, is unlikely to take this snub lying down. The consequence of this – outright war between sovereign and heir – is depressing for those who believe in maintaining the monarchy in this country.

Which brings us back to the question of Queen Camilla. The couple marry next Friday. Next Saturday, as is her custom when she is at Windsor, our present monarch will saddle up and go horse riding. A fall – given that she never wears more than a headscarf and that she is approaching the age of 80 – could signal the end of her 52-year reign. And that means that as early as next Saturday we could have two new incumbents at Buckingham Palace – King Charles III and Queen Camilla. Because, as things stand at present, there is absolutely nothing to stop it.

Together as man and wife they will build a strong team – and for those who care about the future of the monarchy, a strong team is what is required in an age where cynicism and apathy could quickly spell an end to royalty.

And yet things are not right and the country – if not Prince Charles – is quick to sense it. Many people feel that despite the fact that Princess Diana died nearly eight years ago, there is an air of hurry and rush about this royal wedding. Clarence House’s woeful inability to organise it properly, and the Queen’s carefully staged move to distance herself from it, have added to that air of discomfort.

But, above all, it is the apparent subterfuge surrounding the whole event which worries people most. In 1981, 750 million people around the world watched as Charles and Diana tied an elaborate knot around the most wonderful fairytale romance ever.

And yet, backstage, the man who married them – Archbishop of Canterbury Dr Robert Runcie – was declaring it “an arranged marriage”. Nobody likes to be fooled once and they are not ready to be fooled again. They want to know precisely whether Camilla will be Queen or not. Hedging and fudging at this stage are likely to provoke even stronger reactions against Camilla in the future.

Hardest-hit in all this is the Queen herself. Never before has she found it necessary to instruct her son and heir to toe the line, but in the incessant repetition of the phrase “low-key” with regard to the wedding (it won’t be), one hears the sovereign’s clear words of caution and warning. It is likely, however, that they are falling on deaf ears.