Knightsbridge is London's pop-up oasis

She has a mobile phone clamped to her face and huge Dior sunglasses picked out with diamante around the rims. I notice that there is a small Gucci logo on the arm of her floor-length burka — Prada and Chanel burkas are also available.

They join the polite café society scene underneath the eau-de-nil awnings outside and order diet Cokes, £15 club sandwiches and plates of pink macaroons. Every single table here at Ladurée, at the Café Rouge opposite and the Patisserie Valerie around the corner, is taken by people from the Gulf states and the Middle East — Abu Dhabi, Saudi Arabia, Qatar, Kuwait and Dubai.

The groups are either well-behaved families with Mum still in her abaya headscarf and big shades, groups of giggly young girls or groups of posturing young boys all in Arab-preppy finery, two or three mobile phones each, keys to Ferraris and Lamborghinis chucked down next to their napkins.

The young women from the more liberated countries of Bahrain and Dubai are dolled up like J-Lo (they must watch an awful lot of MTV back home).The girls who choose to keep wearing their burkas — mostly Saudi Arabians, I am told — are extravagantly made up with kohl-lined eyes and red lipstick.

A subtle courtship ritual may be at play here but if it is, it is too subtle for me to detect. Indeed, there seems to be little or no interaction between the sexes. Everyone pays with cash produced in wads from croc wallets. No wonder locals call the area "Little Kuwait" during August.

For the mega-wealthy oil billionaire families of the Gulf states, summertime means central London. When temperatures at home hit 50 degrees, they flock to the capital for the cool weather, the thriving social scene and the shopping — especially at Harrods which is, rather neatly, now owned by the Qatari royal family's investment arm.

Some keep summer houses in London — there are said to be more than 100 billionaire Saudi families with second homes in the Knightsbridge area alone — while others prefer out-of-town locations such as Bishops Avenue, Coombe Hill in Kingston and St George's Hill in Weybridge.

They'll go to the Derby, Royal Ascot and the Berkshire Festival of Falconry, which is sponsored by the Abu Dhabi-based Emirates Falconers' Club and attended by His Highness Sheikh Sultan Bin Tahnoon Al Nahyan.

Otherwise, whole floors of hotels around Hyde Park — the Jumeirah Carlton Tower now owned by the famous Dubai group and the Four Seasons Hotel, owned by Prince Alwaleed Bin Talal Al-Saud (who also owns the Savoy Hotel) — are block-booked.

During the days, the women have their drivers drop them in Hyde Park where they promenade around the Serpentine, stopping to soak up the coolness and cloudy skies on the benches or laying out on the grass in large circles with their friends. And then there's shopping.

The men rise later, do some shopping (lots of gift-giving to do on these holidays), maybe head to the cafés of Edgware Road for quail eggs and brioche or smoke a bit of sheesha, then get into their cars for a cruise.

This influx of super-rich holidaymakers and others attracted by such wealth has not pleased everyone. Last year, the Evening Standard reported how complaints from people living in the area adjacent to Ladurée had led to summertime tension. Beggars, drug deals and road rage-generated fist-fights were mentioned.

This year police have reacted by issuing an anti-social order around the busy café that lasts from April 1 to September 30; all summer long, basically. Now anyone creating a nuisance in a zone that extends from West Yeoman's Row, Lennox Gardens, Ovington Square, Brompton Road, Lowndes Square and Pont Street, can be removed, and rowdy, revving groups can be quickly dispersed.

But the first anti-social behaviour order in Knightsbridge history doesn't seem to have put anyone off.

London, especially during these straitened times, does go to great lengths to court Arab business. When the people at Harvey Nics discovered that the year-on-year Arabic spend figures in the Knightsbridge area were showing a 66 per cent increase, the department store extended its hours to 9pm all week and the Fifth Floor food hall got a sheesha smoking terrace. An advertising campaign with a playful Arabic creative theme showed a picture of a single Lanvin shoe. The strapline below, written in Arabic, read "The English are known for having bad teeth, that is why they need beautiful shoes."

But what's the big deal about shabby old London anyway? Yes, we have nice shoes, but can't you get those anywhere? Doesn't our capital seem a bit old and worn compared with bandbox-new Saudi?

"Many of the visitors from the Gulf states will tell you that they come to London because, unlike in the US or France, they are made to feel welcome here," says Hussam Baramo, a Syrian-born, London-based features editor at Al Quds newspaper.

"Many of the younger, more fashion-conscious visitors from Qatar, Dubai and Bahrain even prefer to speak English (rather than Arabic) to each other, throwing in bits of youth slang they have learned off the TV.

"They think this is more modern. You hear reports of women getting changed out of their burkas on the aeroplane so that they can feel free as soon as they land. They like London because they think it is safe and friendly."

However, London is just a holiday, and once the temperature drops, westernised behaviour is put aside for another year. All the shopping and beautiful cars are loaded onto private planes and everyone heads home for the start, on August 11 this year, of the holy month of Ramadan.