One of the mysteries of the Royal yacht affair is why the Prime Minister has been so determined to press ahead with it when the monarch, and the heir to the throne, are understood to be less than wholly enthusiastic.

The new yacht – or trade barge – will cost at least £200m and government departments have been playing pass the parcel with the question of who will pay for it. The answer is… you, the hard-pressed taxpayer.

Sensitive to public opinion, particularly after the Covid travails, the Royals have been determined to ensure that it does not look as they are pushing for a yacht when it could easily turn out to over-run on cost and be unpopular in some future recession.

But Boris is gripped by the brilliance of the idea, partly because he loves grand, boosterish projects. But that alone does not explain the extent of his enthusiasm, especially when the sensible Queen, who has seen many PMs come and go, is lukewarm.

Now, on the horizon, on the starboard side, comes an explanation via a long-time journalistic associate of the Prime Minister.

It is, he says, very important to Boris that he stays “on-side” with the Telegraph owners, the Barclays. They paid him £250,000 per year for a weekly column before he became Prime Minister. If Boris leaves office he’ll need ready cash quickly, while an advance is negotiated on his memoirs. There’s always an element of risk there. Who knows what the circumstances will be or how quick the memoir money will turn up? It may impact on his bargaining power if he leaves office under a cloud. He’ll need reliable payola from day numero uno.

He’ll need that column:

“Cripes, Bojo is back on the old DT… what did I miss? Let’s get things going with a shaggy dog story about the latest, crazed rules and and gut-rot regulations dreamed up, I know not why, dear reader, by what passes for this so-called Tory government.”

And so on, for 1250 words.

The new yacht has been championed incessantly by the Telegraph group, when the rest of Fleet Street declined to take it seriously.

“Boris needs his column back when he leaves office,” says a former colleague of the PM. “The yacht is a Telegraph project with the backing of the owners. Boris must deliver a yacht. He has promised a yacht. He can do nothing to risk his column.”