Perhaps you’re aware that it’s Ramadan right now, the month in which all good Muslims refrain from eating, drinking, smoking and sex during daylight. What you might not know is that Ramadan also marks the start of an annual turf war in London; a battle between the tribal Sloanes and the young Gulf Arabs to dominate Chelsea.

The skirmish actually begins before Ramadan. The Gulf States heat up to an intolerable degree and their oil-rich young migrate over here in droves to escape both religious censure and the sun. They descend first of all on the department stores in what’s become known as the Harrods Hajj, to flash their cash around. One friend of mine working in Selfridges was asked by a young Saudi what she would like as a present. ‘A diamond ring,’ she replied, joking. The next day the customer was back — with the ring.

Fashionable clothing stores in Kensington and Chelsea time their grand openings to coincide with Ramadan, which makes perfect sense when you consider that the ‘Ramadan rush’ made about £150 million for London retailers last year. And where best to show off all the bling? Well, the King’s Road of course, from the front seat of a burnt-orange Lamborghini.

This is where the natives of SW1 and SW3 start to become restless. Thirty years ago, Sloane Square was known for one thing and one thing only: the Sloane Ranger. Knightsbridge was the favoured stomping ground of every London-based Sloane, and as Peter York’s 1982 book The Official Sloane Ranger Handbook put it: ‘How many miles from “the centre” you are is, of course, measured from Sloane Square.’ Back then, tweed, gilets and red trousers were all the rage, and a princess was a style icon.

Some of this might sound familiar. But one thing has changed. These days, Sloane Square simply isn’t Sloane central any more. As Arabs dominate the King’s Road, so the young Sloanes slink further afield, to Fulham and Parsons Green, grumbling as they go. The ever-increasing price of London property means that many of those who have faithfully circled Sloane Square for years now can’t afford to live anywhere near their spiritual home. They’ve migrated further afield, leaving SW1 and SW3 to oil money.

According to one estate agent based in the Royal Borough, cash purchases are common, and many of their new customers ‘don’t even bother visiting properties before they buy’. There is mention of a Saudi Arabian woman buying a house in Chelsea Green (average price for a two-bedroom house: £3 million) for the sole purpose of storing her dresses.

It’s the supercharged Koenigseggs, Bugattis and Maseratis that probably upset the long-time residents the most. Their hearts sink as ‘Arab supercar season’ gets underway. The ‘carparazzi’, attracted by the sound of revving engines, dedicate whole websites to the machines, many of which are shipped over specially for the summer. A Lamborghini Aventador recently made headlines when it was filmed crashing into a Mazda on Sloane Street. King’s Road in summer can feel like a real-life version of the computer game Grand Theft Auto, with shiny vehicles parked willy-nilly outside bars and cafés, and the Metropolitan Police last year seized a large number of uninsured supercars, including one particularly tasteful ‘glow in the dark’ Lamborghini. But there are plenty still roaring around.

Posing and shopping are the visitors’ main hobbies, but they aren’t the only things that bring them from the Gulf to London. It’s the whole experience, from clubbing and drinking to gambling. Last summer, for example, a group of Arab women visited the lesbian drinking spot Candy Bar in Soho; their religion might not allow them to go clubbing normally, but they were permitted to go there as their jealous menfolk deemed it a safe female space.

Naturally enough, Arab Londoners have their own bugbears about the other inhabitants of their adopted city. I heard tell of a Saudi child who said to his private tutor that he was fed up with food from Harrods, but his mother refused to shop in Waitrose ‘because it is full of Russians’.

Of course, the truth is that many of the original Sloane Rangers were priced out of K&C long ago. But the trouble is that where Sloanes go, foreign investors follow. Suddenly Fulham has become a popular choice of third home for families escaping the Emirati heat. Thus prices rise, and Sloanes are forced to move ever further afield — to Acton, Balham, and even Brixton.

There are still some strongholds though, where the old-timers can gather to moan. The Thatcher-themed Maggie’s Club on Fulham Road holds no appeal for your average Gulf playboy, and the Berlusconi-inspired Bunga Bunga bar in Battersea also remains Sloane central.

As long as Sloanes stick to themed parties and fancy dress, they’ll probably be OK. Old habits die hard after all, and no one dresses up quite like a hooray. And as the Handbook says: ‘Sloane is a state of mind — not simply a place.’