When the Prince of Wales arrived at Westminster Abbey for the Commonwealth Day Service on Monday, March 9th, he greeted waiting dignitaries with a cheery “namaste”, a small bow with his hands clasped together as if in prayer. At the time, it seemed little more than an amusing idiosyncrasy, inspiring little comment on a day when all eyes had been on Prince Harry and Meghan and their final outing before leaving Britain. With the benefit of hindsight, after Prince Charles was diagnosed with the highly contagious coronavirus, those he met may be thanking their lucky stars for his caution. On that day he and the Duchess of Cornwall, who has not been diagnosed with the virus yet, spent time - at varying distances - with the Queen, Duke and Duchess of Cambridge, Duke and Duchess of Sussex, the Wessexes, the Prime Minister, some of the most senior clergy in the land, leaders from throughout the Commonwealth, and some 2,000 guests at the Abbey. Though he did not, according to doctors, have the virus then even in its incubation stage, he will no doubt look back with mixed feelings at what will now certainly be the last grand Royal gathering for quite some time. Aides have been tracing anyone who has been in contact with the Prince since March 13th, the earliest “conservative” estimate at which he may have become contagious, to let them know . “It is not possible to ascertain from whom the Prince caught the virus, owing to the high number of engagements he carried out in his public role during recent weeks,” Clarence House said on Wednesday. The days leading up to it, however, hold some significant clues. On March 10th, the Prince of Wales attended a meeting at a water and climate summit in Kings Palace, London, delivering a few words as President of WaterAid. Sitting opposite him was Prince Albert of Monaco, shown below, who, nine days later, would announce that he had tested positive for Covid 19 and said he could have contracted it "at any point in the last ten days or so."

Prince Charles and Prince Albert of Monaco sit opposite each other Credit : PA Video/PA Wire

“I am rushing from one roundtable to another,” Prince Charles told guests, never happier than in the thick of technical discussions on the environment. “We have been convening next door in a rather small room with a lot of people.” On the 11th, he held a series of meetings at Clarence House before deploying his “namaste” greeting to all and sundry at the star-filled Prince’s Trust award, with those including Ronnie Wood, 72, now considered at risk because of their age. “It’s just so hard to remember not to,” he said, mock-exasperated at his repeated attempts to offer a handshake before catching himself under the new rules.

Prince Charles greets Pierce Brosnan at the Prince's Trust award Credit : Getty Images Europe

But it is the 12th - the day before doctors say he could have been contagious - that may be weighing most heavily on his mind. Then, he met scores of people as he hosted an investiture ceremony at Buckingham Palace, as well as holding meetings with senior figures including outgoing Governor of the Bank of England, Mark Carney. Critically, on that morning, he popped into see his 93-year-old mother at the palace: their last face-to-face encounter before they moved to practice government advice on “social distancing”. His father the Duke of Edinburgh, 98, was not there for the catch-up, which surely included conversation about the only topic on the nation’s lips: coronavirus. A week later, the Queen made her way to Windsor Castle for semi-self-isolation in her private apartments as a “sensible precaution”, intended to be seen as leading by example for her generation. It later emerged that a member of staff at Buckingham Palace had tested positive for Covid-19.

The Queen leaves Buckingham Palace for Windsor on March 19 Credit : Aaron Chown/PA

Prince Charles, meanwhile, held his last public engagement that evening, the 12th, at a Mansion House dinner in aid of the Australian bushfire relief and recovery effort. The next day, Friday 13th he made his way to Highgrove, his estate in Gloucestershire, where he spent a week at home amid the glorious spring flowers of his famous gardens. A “small number” of private meetings were held, aides said, as he got on with Highgrove and Duchy of Cornwall business, with all those invited now tracked down. Over the weekend, from Saturday 21st onwards, the Prince began feeling a little unwell. Mild symptoms appeared and did not shift; enough for the generally robust Prince to be under the weather, but not sufficient to raise any alarm bells. That Sunday, he and the Duchess of Cornwall took a flight - not commercial, a source stressed - to Aberdeenshire, and their beloved Scottish bolthole of Birkhall, arriving that evening. By Monday, he was sufficiently unwell that a doctor was consulted. A test, procured and taken on Monday under the NHS, showed the Prince was positive for Covid-19. The Duchess has tested negative, so far. And so the 14-bedroom Birkhall, once described by the late Queen Mother as a “small, big house”, has become a makeshift quarantine fit for a future king. The Prince and Duchess are in separate quarters, with a domestic staff of around half a dozen keeping the house running without seeing them and without entering the local community.

Prince Charles at Birkhall in this file photo from 2012 Credit : Andrew Milligan/PA