Queen Camilla. Once a far-fetched prospect, now a reality – when the day comes – thanks to this extraordinary intervention by the Queen.

No one sensible would have put money on such an outcome in November 1995 after Diana, Princess of Wales declared in her infamous Panorama interview that ‘there were three of us in this marriage, so it was a bit crowded’. Such was the antipathy towards Camilla and the near adoration for Diana, that a totally false story of someone throwing bread rolls at the future duchess in a supermarket car park took hold in the public consciousness.

Mindful of this antipathy – and the polls that said people wouldn’t stomach Camilla being crowned – the Queen has taken her time. Quite a bit of time. In 1998, a year after Diana’s death, she didn’t attend Prince Charles’ 50th birthday party because the then Camilla Parker-Bowles was a guest. The two women only met formally two years later.

Palace and public sensitivities – plus the haunting spectral presence of the ‘People’s Princess’ – meant that before the Queen’s eldest son married for a second time a statement was issued with the following wording, ‘it is intended that Mrs Parker Bowles should use the title HRH The Princess Consort when The Prince of Wales accedes to The Throne’.

In the intervening years, Charles has made no secret of the fact he wasn’t happy at the prospect of his second wife receiving a downgraded title when he became king. And Camilla has been canny. She’s kept the media close and the Daily Mail even closer. Once described by one of her husband’s senior officials as “the laziest woman in Britain” she’s adopted serious causes such as violence against women and made timely interventions.

Crucially, for those around him, the future king is much more relaxed and less Eeyorish when his wife is by his side. Nearly two decades of, at times, quite light Windsor toil have led to the inclusion of 24 very striking words in the Queen’s Accession Day message. Referring to when Charles succeeds her, the Queen writes ‘it is my sincere wish that, when that time comes, Camilla will be known as Queen Consort as she continues her own loyal service’.

So why has the Queen acted now, at the start of the celebrations for her Platinum Jubilee? In one sense, despite the deep public misgivings in the past, she is acknowledging a centuries old custom whereby the wife of a king automatically becomes a queen consort.

However, Charles and Camilla’s troubled history had meant this couldn’t necessarily be guaranteed at his coronation. Not anymore.

Dynastic preservation courses through the veins of Elizabeth the Second. Last month, she stripped Prince Andrew of his patronages. This month, she’s ensuring the transition to Charles as king is as seamless and trouble free as possible. The Queen is future proofing an institution she’s been at the head of for seventy years.

The ringing endorsement of Camilla overshadows the rest of the text where, as she did first in 1947, the Queen pledges that her life will always be devoted to service.

A noticeably frailer 95-year-old, who now uses a walking stick, will continue to reign.

The message shows that the power lies in the court of Prince Charles and its impact, for the Duchess of Cornwall, is considerable. She’s gone from being the third person in a marriage to Queen-in-waiting.

Camilla has come in from the cold.