In Marrakesh for a couple of days' rest and relaxation I have been catching up on my reading. As well as Tom Watson's Dial M For Murdoch and Martha Gellhorn's Travels with Myself and Another, I am ashamed to say that I succumbed to reading Tom Bower's book about the surprisingly vacuous life of Simon Cowell, Sweet Revenge. One of the stories was about Cowell's being refused entry to a hotel in Antigua because he was wearing a T-shirt. This refusal led him, in a slightly confused fashion, to a meeting with Michael Winner who introduced him to the Sandy Lane Hotel in Barbados, a place I have never visited and never want to.

I was interested in the story only because, that very morning, I had been refused entry to a hotel for wearing shorts in the 30C Moroccan heat. These were tasteful shorts that hung below the knee – fairly standard attire in places an hour north of the Sahara. The hotel was La Mamounia, possibly the best known in the whole African continent and, until this incident, one of my favourite places in the world.

Winston Churchill loved the hotel gardens and used to go there to paint, and it has seemingly been an oasis of serenity and good taste since time immemorial. I've stayed there so many times I've lost count, and in moments of stress I always used to console myself that it was only a three-hour flight away.

I console myself no longer. The hotel has been revamped and is now very much not to the taste of the old clientele. Residents are challenged at the gates and inside the hotel by security patrols who make them wait while details of whether they are staying there are verified. Visitors, who used to pop in for a drink or a wander round the gardens, are given short shrift and refused entry for some sartorial crime or told that everywhere is "full".

Marrakechis I spoke to were also up in arms. One told me that La Mamounia was part of Marrakech's heritage and the decision basically to ban "locals" had caused an outrage. "I can walk into the Ritz in Paris in swimming trunks and they would open the door for me," said one. "La Mamounia is the only hotel in the world I cannot visit."

Having read Tom Bower's book, I know this man would also have problems in Antigua, but I totally got his point. I can understand a hotel wanting to maintain some form of exclusivity, but La Mamounia has taken this to a ludicrous extreme. In the grand old days of the Establishment, it was not what you wore but how you behaved that was the mark of the man. Guests in some disarray after a dusty trip into the desert would be welcomed back with a glass of mint tea.

Having said this, I have stayed at La Mamounia on separate occasions when Michael Winner and then Piers Morgan were staying. Morgan spent most of his time wandering around the pool carrying his recently published memoirs in a see-through bag. Winner took up a corner of the pool area and barked at attendants like a beached sealion.

With the new regime, they would probably both still be allowed in while Churchill, who had a weakness for baggy shorts in the tropics, would be refused entry at the gates. Shame.