“Nice try!” was the then-Prime Minister Boris Johnson’s response when he was asked by reporters about the original, disastrous interview with the man who was until 48 hours ago afforded his title Prince Andrew, back in 2019.

That just about sums up the response – for years. Ministers would rather do almost anything than speak out on the saga.

“It was more than being allergic – you were going into a no-win scenario,” a former No 10 official recalls. “You either incur the wrath of the Palace, or you look like you are defending the indefensible.”

The avoid-it-if-you-possibly-can tactic was not just associated with the long-running Andrew saga. For many years, the broad convention has been that senior politicians who want to get near government keep their mouths diplomatically shut about the royals, aside from bland praise, or supportive quiet murmuring.

And the convention worked both ways – with the Royal Family never talking about political matters in public. Polite nods in both directions were the order of the day. It has been deliberate – “don’t upset the Queen, don’t upset the King.”

In our political system, it’s hard to think of other areas where there is the same kind of unwritten rule. The former No 10 source says the prime minister is rarely told to not do something, but when it comes to the royals, aides and officials are “preprogrammed” to advise: do not get involved.