What I am about to say may shock you so if ­necessary, steady your nerves now.
Have another cup of tea, or something stronger. Sit down in a comfortable chair of a kind that is not easy to fall off.
There is a case for saying that the Andrew formerly known as Prince – aka Mountbatten-Windsor – has not only done his country a service but is the best thing to have happened to the Royal Family for years.
You all right there? Everything OK? Let me explain.

I first met him years ago (see my memoir Unleashed, still selling strongly) when I was Mayor of ­London. I have to admit that I was a bit grumpy to be told that I had been summoned to meet Prince Andrew. But my brilliant Private Secretary, Roisha Hughes, was adamant.
You have got to go, she told me. The Prince was then the government’s official trade envoy. So, we did. We went off to tea at Buckingham ­Palace, and it was all a bit bizarre.
The Duke of York had a series of ideas, perhaps gleaned from some of his international contacts, about how we could make London even more attractive to the world’s billionaire investors. Bear in mind that this was back in the good old days, before Starmer’s Pol Pot war on wealth ­creators. ­London at the time had more billionaires than any other city in the world.
But the Duke thought that we could do better. Look at ­Battersea Power Station, he said.

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It was an eyesore, a ruin. It was blocking development of a huge and potentially lucrative site at Vauxhall.
‘Why don’t we just knock it down,’ he said. As it happens, I had brought with me the late Sir Simon Milton, my wonderful deputy mayor. Simon tried to explain that the former power station was an architectural masterpiece. It was listed Grade 1, part of our cultural heritage. We were sure we could develop the site, but without destruction.
Andrew was unconvinced. ‘It’ll never happen,’ he said.
Well, what about this building, said Simon, waving his hand at the vast but gloomy room. It was an amazing site, a truly prime development opportunity. Why don’t we knock down Buckingham Palace, asked my deputy?
Andrew glared – but rallied. Another thing, he said: a lot of his friends, potentially very significant investors, were complaining about Heathrow. There were ­terrible queues at immigration. Not enough of them were allowed to use the VIP suite.
He had heard about my proposal for a much bigger and more efficient airport in the Thames estuary. He knew that one of the objections was the presence in the waters of a sunken World War II munitions boat called the SS Richard Montgomery.
He had a brilliant solution. Why not make a huge steel net and wrap it round the wreck so that if it exploded the shock waves would not damage the airport?
Right-oh, we said, pretending to take a note. One other thing, Andrew added: a lot of his friends were utterly fed up with the ­traffic. It was damaging London’s reputation.
Suppose you wanted to leave town on a Friday afternoon, he said: well you could be delayed for hours. What about rephasing the traffic lights so as to give more time on green for everyone heading off for the weekend?
I tried to persuade him that actually we did something of the kind (called Split Cycle Offset Optimisation Technique, or Scoot, since you ask), but that there were limits to what you could do, what with the cross-traffic and so on.
I could tell that our answers hadn’t really satisfied him, and that he had visions of billionaires being waved through Heathrow and through a series of green and deferential traffic lights to look hungrily at building sites being cleared of pesky heritage ­buildings. As we left, I am told I made some salty and unworthy remarks.
But in a way I felt a bit sorry for him. He was the second son in a system that insisted on male ­primogeniture. The result was that he didn’t have a role. But now, he does.
Did you see the relief, the exuberance, with which the crowds greeted the Prince and Princess of Wales this week?
Is it possible that Andrew’s ghastly pratfalls have actually intensified their enthusiasm? Like taking off a pair of ill-fitting ski boots, or suddenly basking in the sunshine after a sodden and miserable British winter, the pleasure is all in the contrast.

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We look up from reading about Andrew Mountbatten-Windsor and Epstein and Mandelson, and all the horrific things that seem to have happened on that Caribbean island, and we have such a creepy sense of a conspiracy involving money and power and sexual dissolution that we feel we have been fire-hosed with slurry.
And then we look at the other members of the Royal Family, and think how relatively decent and public-spirited they seem. How fine and how regal the King appears, what with his rather good watercolours and his interest in architecture and the ­environment by comparison – and this is the key point – with his brother. The second long – and indeed the last conversation I had with Andrew – took place when I was PM, and I was for some reason deputed to tell him that he could not attend some big public ­ceremony, for fear of embarrassing his mother and the whole institution of the monarchy.
This time I had to go to Windsor to break the bad news.
He was not thrilled. I tried to cheer him up.
Look, I said, he needed to be a bit humble. He had to understand how people felt about things, ever since that disastrous interview on Newsnight. He needed to build back his reputation.

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Why not open a pub in the country, and run it with his ex-wife Fergie? She seemed to have the right sort of breezy personality.
‘You could call it the Duke of York,’ I suggested. He looked at me sharply, as though I was ­pulling his leg. But I wasn’t, really. Andrew’s tragedy is that he could never find anything ­useful or practical to do and so gave in to the appalling ­temptations that came his way.
He will now face a long time of trial, in which things will get worse before they get better.
But has he advanced the republican cause? Not an inch.
Think of all the potential ­‘Presidents of Britain’. Actually, I am struggling, but let’s suppose it was a shoot-out between ­Jeremy Clarkson and Sandi ­Toksvig and some has-been ­centrist politician. You only have to frame it like that to see how ghastly and polarised it would all become – just like everything else these days.
The mere thought of it makes us shudder and appreciate what we have – a romantic cultural asset of incomparable global reach, a person whose genes actually embody UK history, who gives continual service but ­steadfastly refuses to get involved in political questions.
It’s precisely because he makes us shudder, and think of the alternative, that Andrew has done the monarchy a favour. He has made them more intelligible to us, too, because every family has a black sheep or two.
By the sheer scale of his disgrace, he has paradoxically intensified the dignity of the crown.