Rachel Johnson: I'm already in mourning for the death of Notting Hill

If I leave the 'hood for two weeks, a beloved shop will be gone. The unique selling point of Portobello will vanish for ever

As the world descends on a small, stucco-faced, late Victorian neighbourhood in London today for the start of the annual carnival, Notting Hill is wobbling on its axis. Not only are two million people over the course of two days too much to cope with. But that's nothing compared to the threat of brand retail and greedy developers, both of which could shortly take one of this country's few remaining unique shopping streets the same way as every other high street in Britain. The news that yet more sole traders in the Portobello Road have bitten the dust comes as no surprise. Frankly, I'm still in widow's weeds after the closure of Italian restaurant Zucca on Westbourne Grove (which Notting Hill Tories made their local canteen) and Felicitous (the deli owned by Lady Osborne, mother of George, the Conservative shadow chancellor).

I've lived here for 25 years, and just published a book that sets out the area's subjection to insatiable landlords and skyrocketing property prices. (I can't bring myself to say decline, because that sounds like a self-fulfilling prophecy.)

If I leave the 'hood for as little as two weeks, some much-loved independent shop I've known all my adult life will be gone by the time I return. Portobello Road will soon look no different from Oxford Street. The 200 or so independent retailers selling Welsh blankets, vinyl records or organic baby clothes are under constant attack from the clone-brand "bland" retailers that disfigure every other high street.

Adrian Palengat, the owner of Apart, the contemporary art gallery that has just closed was frequented by the Gallaghers, Minnie Driver and Keith Flint of Prodigy, sets out what happens to an independent retailer under an Attack of the Clones. "In 1999, I wanted to open a business that focused on young artists and young buyers because I felt nowhere else in London did this. We traded for five years, making a modest return. But when our first rent review came up, we were effectively evicted."

Another sole trader, antique dealer Katrina Phillips, tells the same sorry tale to the Friends of Portobello action group. "My father was here before me in 1967. In June 2004 I took it over," she told them. "The rent was about £50,000, then in the first year Levinson, my landlord, increased it to near £60,000. Next, out of the blue, I got a letter addressed to my dead father saying the rent was to be £79,000. I said I'd spent £55,000 on improvements and the landlords replied it was a full-repairing lease, and sent me letters threatening bailiffs. We've been here for nearly 40 years."

I am particularly sad, though, that Culture Shack has gone. A favourite of 30 years' vintage, with hipster designers such as Bella Freud, as well as grey-dreaded rastas in One Love knitted berets and Haile Selassie T-shirts, this comes as a real blow. In both their places will arrive brand retailers or boutiques selling overpriced, clothes or new restaurants.

Belatedly, the town hall has acted to protect its brands. Too late it has realised that what shoppers want from Notting Hill is not the same thing as they get from every other identikit, Tescified high street. Too late it has established a retail commission under Sir Terence Conran. But unless the planning laws change, landowners will go on charging extortionate rents.

Only if the borough slaps a protection order on our 'hood to make it a slow shopping area, like Marylebone High Street, the centre of Paris, or Ludlow in Shropshire, will it be saved. Otherwise Portobello Road will become a clone area like everywhere else.

Rachel Johnson's 'Notting Hell' is published by Penguin