Parodists strive to imitate my plummy English voice, one of the last to remain outside captivity, but it is beyond their range. They never lived in a world where it was normal, and so only hear parts of it.

I confess that, when in the US, I turn it up a bit, as that country is still (rightly) secretly ashamed of what it has done to the English language. 

I might also do so in Oxbridge debates where I suspect it still whispers a coded message to some of my listeners. That message is that an accent like mine is evidence of authority and knowledge, which it is not really.

This is probably a mistake, as I have lost the vote (though not the argument) at almost all the Oxford or Cambridge Union debates I have taken part in. 

Once upon a time, the tones of John Snagge and Alvar Lidell were a guarantee of reliability and trustworthiness. But in the 21st century, the plummy man is always wrong. And that is why I shall soon be not just marginalised, but extinct.

So I am puzzled by the claim of that fine actress, Erin Doherty, that the accent she adopted when she played Princess Anne in the TV series The Crown helped her get better service in coffee bars. 

‘I remember ordering coffees in a Princess Anne voice,’ she says, ‘and it was massively different, which was interesting. Without being stereotypical, it got me my way quicker. My coffee was in my hand.’

When Peter Hitchens is in the US, he turns his plummy voice up a bit, as that country is still (rightly) secretly ashamed of what it has done to the English language

Erin Doherty claims that the accent she adopted when she played Princess Anne in the TV series The Crown helped her get better service in coffee bars 

This seems unlikely. Apart from anything else, most coffee shops in modern England are staffed by people from Eastern Europe, who can’t tell posh from Essex. She says: ‘There’s an authority to voices like that. And whether we like it or not, you respond differently.’

Well, I would say there used to be. But for a long time now the Received Pronunciation (RP) voice has been under slow, merciless attack. For many people it symbolises the entitlement of the privately educated.

And I have interesting research which suggests it has been in retreat for many decades. First, listen to recordings of the late Queen early in her reign when she spoke of ‘hets and hendbegs’. 

Or listen to the tones of upper-crust actors in 1950s films, such as Terry-Thomas in I’m All Right Jack. Nobody has talked like that for half a century.

After my naval officer father died in 1987, my uncle unearthed some ancient spools of old-fashioned tape recordings from the early 1960s, in which my father had sent Christmas messages to our cousins then in South Africa. 

The way he pronounced the name ‘Janet’ could have come out of a Movietone news commentary on the 1938 Munich Agreement.