F. Scott Fitzgerald got it wrong; it’s not the rich who are different from you and me — it’s the posh. There is no social act so rude or outrageous that it cannot be explained and then excused on the grounds that the perpetrator was posh.

I was recently at a drinks party and saw a man scratching his bottom in front of the buffet table — a full, hand-down–trouser buttock-scratch. With the very same hand that he’d used on his bottom, he picked up a sausage, examined it and put it back in the pile. He then picked up another sausage and put it back. Then, after another quick bottom–scratch, he began to poke around the samosas.

Cosmo Landesman debates the posh with etiquette guru Liz Brewer:

The thought that maybe it was inconsiderate to indulge in bottom-scratching and sausage-hunting with the same hand never occurred to this man. When I confronted him with the antisocial nature of his actions, instead of reacting with acute embarrassment and a profusion of apologies, he just laughed and went off, no doubt, to fondle other bits of party food.

I informed our hostess about what I had witnessed, adding, ‘He must be totally pissed!’ But instead of sharing my sense of concern she shrugged her shoulders and said, ‘Oh no, he’s not pissed. He’s just posh.’

It’s amazing the way middle-class society will make excuses for the bad behaviour of someone whom it believes to be posh. If a guest is drunk, makes a pass at your wife or your teenage daughter, vomits all over your sofa and passes out on your living room floor, it’s perfectly OK — as long as he’s posh.

I know this because I know a man who did just that at a dinner party a year ago — and not for the first time. Outrageous behaviour is his party piece. (A mutual friend tells me that he ‘vomits on my shoes every time I see him. It’s fine.’) Is the man a social pariah, shunned by society? Are you kidding? He’s a much-loved living legend who is always in social demand. But then he’s from one of those very old and terribly posh Catholic families.

Being posh gives you all sorts of privileges — even if you’re a drug addict. A posh junkie is regarded with concern and fascination, for he or she has the alluring whiff of decadence, that aura of ancestral doom. The spectacle of posh people with addictions or psychological problems has always enthralled the literary-minded, from Evelyn Waugh’s Sebastian Flyte to Edward St Aubyn’s Patrick Melrose. By contrast, nobody cares or is interested in a common-or-garden council-estate heroin addict. A posh addict who overdoses and dies is a tragedy; a prole who overdoses and dies is a statistic.

And when it comes to crazy, people adore a posh girl who is bonkers. A friend wanted to fix me up with just such a girl he had dated. ‘She’s completely mad — you’ll love her,’ he said.

I told him, ‘I’m finished with crazy women.’

‘But this one is different. She’s crazy and posh.’

‘You mean she’s a better class of lunatic?’

‘Exactly!’

My friend then regaled me with supposedly hilarious tales of the woman’s antics that proved her poshness. They included setting fire to his bedsheets, peeing in his sink and slipping his mother a tab of ecstasy.

What I object to is not the bad behaviour of these individuals so much as the double standards of posh apologists. It is the snobbery of the social climber who indulges the posh and condemns the rest of us that grates.

How are we to explain this privileging of the posh? After all, we like to think that we are becoming a more meritocratic society, one that refuses to confer special rights and privileges upon any one class or social tribe. Consequently, we all have to play by the same social rules.

Why not the posh? Peter York, author of The Sloane Ranger Handbook, tells me, ‘People think it’s OK for the posh to behave badly in society because they think it’s their culture; a part of their tribal customs and traditions. It’s something they just do.’

Another reason is that the middle class fear that should they object to the anti-social antics of the posh they will expose themselves as middle-class, ‘bourgeois’ or, even worse, ‘suburban’.

Many metropolitan middle-class people envy what they see as the insouciance of the posh. To be middle-class is to live in constant fear of saying and doing the wrong things. We are always apologising for the most minor of mistakes or mishaps. The posh, on the other hand, are totally free of such social anxieties or regrets.

Imagine going to a dinner party and causing a blockage in the host’s toilet. It’s the great middle-class social nightmare — combining the twin horrors of poo exposure and property damage. It’s something that would haunt a middle-class person for the rest of their life. The next day they would send a vast bouquet of flowers and a letter begging for forgiveness, offers to arrange for a plumber and payment of fees. A posh person would just send a card saying, ‘Lovely evening. Thanks. x’

The posh are celebrated for this sort of ‘insouciance’ — but this is just a fancy word for being a selfish, self-centred and thoughtless dickhead. Working-class people aren’t impressed by the antics of the posh: to them such behaviour is out of order.

It’s ironic that in our post-Brexit Britain, where the people — their wishes, their views — are now sacrosanct, we hear very little talk about the upper class. We moan a lot about the ‘metropolitan elite’ but we are blind when it comes to the outmoded sense of entitlement, the unjustifiable privilege and the licensed bad behaviour of people who just happen to be well-born.

Me, I prefer the restraint, politeness and good manners of the over-apologetic and anxious middle class to the infantile anti-social behaviour of the posh any day.