Back in the 1980s, I seemed to spend half my life traipsing to Covent Garden to hire a dinner jacket and the other half mournfully explaining to the man on the returns desk that it was covered in sick when I rented it.

And that, no, despite the strong smell of chlorine and the fact it was only 6in long, it had most definitely not been in a swimming pool.

What’s more, every wedding, and there was one every weekend from what I remember, required the idiotic combination of a stovepipe hat and a morning suit. Which would then be ruined because I’d have to leave the reception and dash off to throw some food at the chap who was getting hitched the following Saturday. Inevitably, that led to more mournfulness at Moss Bros.

Back in those days, you couldn’t go anywhere without going home first to get changed. Restaurants would turn you away if you weren’t wearing a tie. Gentlemen were required to wear jackets. Shorts were for the playing field, and I was once turned away from Rotters Nitespot in Doncaster because, despite my claims that the jacket was actually velvet, the bouncer was most insistent it was made of corduroy.

Corduroy was a big no-no in Donny back then. Because it was deemed cheap, publicans and club owners felt that you wouldn’t care too much if it were torn in half in a fight. You had to be smart because that way, it was felt, you’d be less likely to stick a pint pot into the face of someone who was looking at you funnily.

Happily, these days things are very different. Last weekend I went to a posh wedding and nobody’s jacket went down to the backs of their knees. I wore a £40 suit I’d had made in Vietnam. One chap was in a pair of Levi’s.

Then, last week, I was at a fundraising event for Palestinian children in London’s glittering West End. Time was, I’d have had to dash into an Indian restaurant on the way to “borrow” a waiter’s bow tie. Not any more. People appeared to be wearing what they’d had on when they finished work. Lily Allen wasn’t even sporting a bra. The hussy.

At the Royal Opera House not that long ago it was all veils and tails. Now they will let you in in your underpants. And why not? Who says that to see a woman on tiptoe you need to be mummified in starch?

I think this casualisation is excellent because if you are staging a get-together, whether it be a fundraising event for the people of Gaza or a wedding, it is absurd to tell your guests what they must wear.

That would be like forcing them not to smoke, or insisting that all the vegetablists eat meat. If you are a host, then it is your duty to make sure that your guests have as nice a time as possible. That means letting them wear and do and eat whatever takes their fancy.

If I invite you round to my house, it’s because I want to spend an evening in your company. And I don’t care about what box you come in. Army boots and a jockstrap? Fine. Naked? That’s fine too. Especially if you are Lily Allen.

However, even today, with liberalism running amok, the dress code has survived. And often you need Colossus to decipher it. “Country casual”; “purple and fun”; “1963”. Or, worst of all, “fancy dress”. I was invited last week to a “white tie and tiara” do and I’m afraid it went the way of all invitations where the host tells the guests what to wear. Into the bin. White tie and tiara? Do me a favour.

The worst offender, however, is Royal Ascot, which trundled into the summer last week with all the welcoming warmth of a bed of rusty nails.

Gentlemen are required to wear a black or a grey morning coat and a top hat that may be removed only in restaurants or in enclosed seating areas. That’s stupid enough but things are so much worse for women, who must wear a hat or a “substantial fascinator”. Nope, I have no idea either.

But then things get really idiotic. You may not bare your midriff, you may not wear a miniskirt, you may not wear anything with a halter neck, and dress straps must be at least 1in across. Anyone whose dress has straps narrower than this will have their royal enclosure pass removed and may or may not be slapped lightly by the Queen.

Amazingly, women are allowed to wear trouser suits, the national costume of the terminally dull, but the trousers must match the jacket. Who dreams this stuff up? It’s not taken from the pages of tradition because women did not wear trouser suits until the glass ceiling was removed in about 1993. It’s recent.

And that means somewhere out there, walking around, with a vote and a driving licence, is a person who actually sat down one day and decided women who wished to see a horse running past them very quickly with a small Irishman on its back would be allowed to wear trousers, but only if they were made from the same material as the jacket.

How empty must your life be to think of such a rule? How pointless and stupid?

It genuinely baffles me because if you reach a point in your existence where you start to worry about whether men should be allowed to wear a hat while eating lunch, then you must have considered and done everything else that life has to offer. Up to and including what it would feel like to put a shotgun in your mouth and pull the trigger.

All a dress code such as this does is encourage the orange and the dim to come along and pretend that they are posh for the day. Meanwhile, the wicked and the interesting are doing something else. In a pair of jeans.

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