My opposition to the monarchy is not just based on the money that could be far better spent on school books and hospital beds.

Nor is it just about the entrenched class divisions it represents, or the psychological harm that being in that family does to its individual members.

Above all it’s the belief among many people that the royals are somehow better than the rest of us. That surely becomes harder to sustain when you consider Prince Andrew’s friendship with paedophile Jeffrey Epstein. They say we are judged by the company we keep.

Still, the monarchy is on the way out. According to a YouGov poll last year, 21 per cent of the population want a republic and 11 per cent don’t care.

But the percentage of republicans among the under-45s is far higher than among those older. And Harry has admitted that none of his generation of royals wants the throne.

It’s only a matter of time before it’s abolished. I give it a couple of decades.

But if we do have to have a royal family – and I guess we’re stuck with them for now – then the least they can do is use their well-paid, privileged positions to promote worthy causes.

Some of them are patrons of charities, though in many cases that means no more than having their name on the headed notepaper. The armies of volunteers and fundraisers among the general population do the real work.

But there are times when even monarchy-sceptics have to congratulate them. I don’t quite know why Princess Diana turned up to a Middlesex hospital to watch a heart operation, except to have her picture taken. But she did speak out against landmines and showed sympathy for Aids victims, which was better than sitting in her palace watching box sets.

Harry and Meghan seem a bit less dull than the others, and have shown a healthy disrespect for some of the sillier conventions.

They were seen holding hands during their first public appearance together, at the Invictus Games in 2017. National papers made much of the fact that she closed the door of a car she got out of. Apparently neither of these are the done thing among our ruling class.

And the couple have announced that they are going to have only one more child, on environmental grounds.

Climate change is not going away and big families are surefire way to add to it.

Researchers from Lund University in Sweden have found that having one fewer child per family could save an average of 58.6 tonnes of CO2 emissions per year.

By contrast, giving up your car would only save 2.4 tonnes and going vegan saves just 0.8 tonnes. Perhaps everyone should limit themselves to a maximum of two kids, like the Sussexes.

Meghan also signalled her green credentials in September’s edition of Vogue, which she was invited to guest-edit. One of the 15 girls and women on the front cover is 16-year-old Swedish climate change campaigner Greta Thunberg.

It would all be a lot more praiseworthy if it wasn’t for their other behaviour. They have taken four private jet trips in just 11 days.

Harry and Meghan took a 12-seater Cessna 680 plane to and from Nice airport, for a holiday with Elton John and family on the French Riviera.

Earlier this month they chartered another private aircraft for a six-day trip to Ibiza.

Aviation is one of the world’s major polluters, responsible for more than two per cent of global emissions, and the environmental footprint of a private plane is much greater than that of a commercial one.

There are more than 20 commercial flights to and from Nice but Sir Elton, who paid for the private ones, justified them by claiming they offered “a high level of much-needed protection”.

I don’t buy that for a second. The couple and their baby could easily have been accompanied by security guards on an ordinary commercial flight. Think how much praise they’d have got for showing that their green principles went beyond practising contraception.

It’s a clear case of: “Do as I say, not as I do.”

Maybe there are still people that believe that baby Archie’s blood is blue, or that Meghan’s turned blue the moment the wedding ring was on her finger. If so there’s no hope for them. Some people will always be deluded.

But the rest of us should know hypocrisy when we see it.