The disappointments of the morning were reversed by three Royals. We were in central London in search of tradition but our trip had gone terribly wrong. Then, with the help of a complete stranger, all was made good as first Princess Anne, then Prince William and finally the Queen, drove slowly past and in touching distance. Now we had something to shout about.

My plan that day was to take Jean-Claude and Armelle to see the Changing of the Guard at Buckingham Palace. They, and their daughter Agathe, were staying with us in London; over here from Brittany where they are our close ‘summertime’ neighbours. Like many of our Breton friends, they had come, in part, to see how we live when we are ‘away’ in our other home. Their visit also allowed them to settle Agathe into her two-month, English language, work experience. She was occupied with just that while we were sightseeing in central London.

We had already visited Kew Gardens, Richmond Park, the Natural History and Victoria and Albert Museums, and had taken a boat trip up the Thames. Now it was time to see some traditional pageantry.

Our first stop was St James’s Palace, where I had planned to give Jean-Claude and Armelle close-up views of rifle-bearing, bearskin-wearing guards standing in sentry boxes and marching along pavements. Well, that was my memory from a visit ten years ago. It soon became clear that everything had since changed. Three, flack-jacketed, armed policemen told us how the guards and their boxes had been moved behind the Palace gates ‘for their own security’; it was now the police who guarded the site. I reassured my guests that the pomp of the Changing of the Guard would make up for this setback. But that offer just ushered in a second blow.

On asking one of the policemen how best we might see the changeover he replied wryly – “You should go home and start again tomorrow – your calculations are a day out”. Shame-faced and embarrassed – I had actually checked dates on the Internet – I explained the muddle to my guests and we trudged off to see the Palace for history’s sake. That is all I could now suggest.

As we approached, I saw the Royal Standard – the Queen’s flag – fluttering on the Palace flagpole. I dreamt that, as she was at home, there was surely a chance that by some magic she might appear. Little did I then know!

After some moments staring forlornly at the Palace through its wrought iron railings, we decided to head off towards Trafalgar Square and Downing Street, but we were stopped. A neatly dressed, straight-backed, guardian angel in his late sixties appeared as if by magic. “Don’t give up. Any minute now something important is going to happen”. “Princess Anne will be leaving the Palace in three minutes. If you stand on the kerb by the gate to your right you will see her as she passes”. “And don’t move – there is more to come”.

The Princess passed, we stayed put, and our magician kept walking over to give us updates – he told us with equal precision how we would soon see Prince William and later the Queen herself. As forecast, one by one the next royals went by, sitting in the back seats of their chauffeur-driven Bentleys. Both Royals sat on ‘our’ side of their cars and, as the gateway was narrow, they were so clearly visible they could be viewed ‘warts and all’. They even waved.

Our magician explained how things worked. He had spent years as a guard at the Palace and, now retired, he could easily see what was happening. By observing the precise movements of the police – armed and unarmed – as they busied themselves around the gate, by watching the positioning of motorcycle outriders lined up in the palace forecourt, and by looking to see if the doors in a gate in the Palace’s north wing were open or closed, he knew exactly what to expect. It was, as he modestly put it, all very obvious.

If seeing the pageantry was not enough, we also learned about ourselves. We were caught up in the waves of enthusiasm and expectation of the other onlookers. Here we were, three, stoical, adults, two of whom were staunch republicans – and French to boot – suddenly showing signs of royalist fervour. Odd as it may seem, that was the case. Moreover, I later learned that the pageantry that morning was one of the highlights of our guests’ London stay.

Amongst their memories there was also the unprompted, mystical kindness of our retiree – a level of kindness they could not fathom. And I feel likewise. He saved the day, and for me he eclipsed the royals but we hardly thanked him. That seems so unjust!