For decades the Queen has shown a unique ability to divine the mood of the nation.
It happened in the aftermath of the Windsor Castle fire when she realised the public willingness to foot the bill to repair a private Royal Family home with taxpayers' money was not forthcoming.
And it happened when, in the midst of an economic downturn, with families across the land facing hardship, she announced that both she and Prince Charles would pay tax on their private income. Both occasions were highly significant.
Only once has that unerring instinct to tap into the public psyche failed her, and that was during the crisis that engulfed and threatened, briefly, to convulse the royals over the death of Princess Diana.
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A row that began over the absence of a flag flying at half-mast over Buckingham Palace as a visible symbol of mourning, and the lack of any expression of sorrow, escalated so much it placed the Queen in danger of appearing coldly out of touch.
Then, if not quite at the 11th hour but perilously close, Her Majesty responded. Protocol was ignored, a flag was lowered and she returned to London from Balmoral to address her people live on television, with the doors of the famous Palace balcony flung open to show the tens of thousands of grief-stricken mourners beyond her in the Mall.
Twenty-three years on from that critical moment and the country is once again looking to the monarch for words of consolation, hope and, above all, reassurance.
She did not disappoint. No national broadcast on this occasion — not yet, anyway. Instead, yesterday, as the coronavirus tightened its terrifying grip on the country, she once again demonstrated infinite experience in a statement issued in her name.
It came as she was reunited with Prince Philip at Windsor, and was brimming with good sense in its appeal to the country to foster a community spirit to protect the vulnerable.
Typically, she reached back through the years of her long life to draw on her own experience of living through the adversity and uncertainty of wartime.
In a passage which echoes that famous Blitz spirit, she said: 'I am reminded that our nation's history has been forged by people and communities coming together to work as one, concentrating our combined efforts with a focus of a common goal.'
The unpredictable nature of the emergency, with its isolation and loneliness, meant, she said, that we would have to find new ways to stay in touch with one another and make sure that our loved ones are safe.
'I am certain,' she added, 'we are up to that challenge.'
Her welcome intervention, which once again demonstrated that she can rise above the opportunist words of politicians, came amid criticism in some quarters that she had been quiet so far. This not only misjudges the Queen's distinctive role as sovereign but is also impertinent.
This, remember, is not a personal family crisis, as Diana's death was, but a national emergency — and it is for Boris Johnson and the Government to ask the Queen when and how to step in.
She has, of course, been ready and willing to do whatever is asked of her. While following the unfolding drama closely, she has also been briefed by her own physicians. The Queen is just weeks away from her 94th birthday and is firmly in the "at risk" demographic of elderly and vulnerable Britons. As indeed is Prince Philip, 98, who yesterday left his own refuge at Sandringham to join the Queen at Windsor.
She has cancelled all official entertaining, receptions and lunches. Investitures, too, have been postponed while essential audiences have been carried out by telephone. About 20 members of the royal household staff, from grooms and footmen to maids, are understood to be self-isolating, but they are not thought to have the virus. Last night, it was claimed one servant had tested positive.
All the same, the Queen has refused to hide herself way, insisting that as far as possible it must be business as usual.
Along with great age, she is also the embodiment of great wisdom. And her strong and enduring memories of World War II informed the measured words she used in her statement. They conjured up far more than just "keep calm and carry on", but also spoke about the healing balm of monarchy.
How different from the clichéd and frankly meaningless contribution from the Duke and Duchess of Sussex on their Sussex Royal website. There may be a time and place for facile and homespun messages, but their preachy post showed a fundamental misunderstanding of the mystique of the royal family.
Harry and Meghan, remember, are not self-isolating at their luxury Canadian bolthole but, rather, choosing to be there in their own splendid isolation — a move they sought themselves in order to be as far away as they can from their old life as royals.
Little wonder online mockery greeted the Instagram post. Their despatch, posted from the vastly expensive mansion that they cannot afford and which is provided by someone whose identity has been kept secret, could not contrast more with the thoughtful and dignified response of the Queen and other royals at home at this time of national crisis.
'We need each other for truth, for support, and to feel less alone during a time that can honestly feel quite scary,' they declared, adding that they will help us all 'navigate the uncertainty' by 'posting accurate information and facts from trusted experts'.
Are they seriously suggesting we have not been told the truth? And that we should trust them to know what is accurate and what is not?
Rather than a period of silence that many at the palace feel is long overdue, the couple promised to post inspiring stories about coronavirus. Empathy and kindness, they said, will be their "guiding principle".
Many will doubtless reflect that being 5000 miles from our fight against the virus makes any contribution from the duke and duchess little more than empty words.
Here, in lockdown Britain, which is more and more beginning to resemble a country at war, the Queen yesterday declared herself ready for the task.
No one articulates a calming presence better than a Queen who can still recall the words of her father King George VI on the outbreak of war in 1939, when he broadcast to a frightened and anxious empire. It began: "In this grave hour, perhaps the most fateful in our history" and spoke of being calm, firm and united in the "dark days ahead".
Princess Elizabeth was just 13, but her father's stirring words have resonated with her ever since. She drew on it for themes in her remarks yesterday.
No nation has ever been more fortunate in its monarch. Only once has she shown she was less sure-footed in her understanding of public opinion and not since 1997. The Queen projects such an extraordinary aura that it is impossible to deny she represents the very essence of our island state.
At a time of crisis we look to her and she, sure as not, responds.
Once before in her long reign she threw herself on the mercy of her critics, appealing for compassion and kindness in the wake of the domestic upheavals of her "annus horribilis". Her place in her countrymen's hearts was never in doubt, and in her statement she showed that the country is in hers.
Now she is safely reunited with her beloved Philip, it is time for others in the family to step up. Both Charles and William will have roles to play in the days ahead.
One of their first tasks should be to remind Harry that he and his wife chose to step down from royal duty and to point out the vapid grandiosity of their media posts from a foreign hideaway.