The Westway Trust has unveiled proposals to brand the area Portobello Village, which partly involves removing an existing canopy where vintage stalls currently operate three days a week and replacing it with a three-storey 'market building' with those traders now on the ground floor.
Next to that, the Portobello Green Arcade with 26 units (including some vintage dealers) would also be rebuilt, and the surrounding public space revamped.
The trust says it is "absolutely committed to retaining the unique character of the area", which it has "successfully managed on behalf of the community for over 40 years". A spokesman said: "The vintage clothing market and the Portobello Road street market are staying and will continue to be supported by the Trust; they are at the heart of the area and will remain so."
However, the proposals have met strong opposition from many locals and shoppers who fear it will change the area's character and drive away the independent small traders who are the lifeblood of the vintage scene.
An online petition calling on the trust to ditch the plans has attracted nearly 16,000 signatures. It was started by Chris Sullivan, who aims to present it to Kensington and Chelsea council and the trust when it hits a target of 20,000 signatures.
Sullivan, who ran Soho's Wag Club in the 1980s and has been involved with Wayne Hemmingway's Vintage Festival, told ATG he started the petition because: "I love that area and the whole ethic behind it and cannot bear to see it sanitised and ruined in the way the Camden Stables (I lived opposite there from 1982-94) and Spitalfields have been.
"I saw the plans and what we would lose and thought I have to try stop this. This will kill W11 and its spirit. My wife grew up just a few hundred yards away in Lancaster Road and I bought a flat a mile or so away in 2002 mainly because of this top end of the market.
"Most Fridays and Saturdays I walk from Maida Vale to Golborne Road and down Portobello to Westbourne Park Road and end up in The Cow for a pint. I always bump into my friends and meet people, get something to eat from one of the food stalls, buy a piece of vintage clothing, a book or bric a brac. It is the hub of the community and as much a social zone as a commercial one."
He added: "This area is one of the last remaining areas in London where you can buy a meal for a fiver, a coat for £20, an old book for £2, an antique for £20 and see independent traders thrive.
"The problem is that it doesn't fit into this new corporate view of the world that we are being pushed to swallow, and is not about huge profit. But the Westway Trust are supposed to be managing this on behalf of the community and we are the community so we will stop them but it will be a fight."
The concerns will be familiar ones to many antique dealers further south along Portobello Road: gentrification is often interpreted as higher rents, chain stores moving in and dealers moving out.
However, it isn't quite that simple. As with the antiques dealers, the vintage stalls only operate a few days a week, meaning landlords who have invested in the area feel frustrated there is not enough trade - or rent coming in - on other days, despite this being a highly popular area for visitors.
The Westway Trust acknowledges this as part of its approach. Its proposal says "the new building will have the potential to house other markets on different days of the week". When asked by ATG for specifics, they said: "It is too early to say, but we will be open to proposals for a range of opportunities outside of the current market operating hours and days."
They added: "Having worked closely with the market operators, Westway Trust recognises that the area around the Portobello Road/Westway intersection is not without its problems. If allowed to continue, these issues are likely to have a growing negative effect on the community and local businesses.
"The markets only currently operate for three days a week. Outside of those days, areas like the canopy space and Acklam Village do little to contribute to the local area. Acklam Village is hoarded-off and not even accessible to the community from Monday to Friday.
"That means that very few people are coming to the area on non-market days and this lack of activity contributes to a poor trading environment and to antisocial behaviour. Many of our own tenants in the Green Arcade are struggling to trade outside of market days, exacerbating the problems of what is in effect a three-day-a-week economy. Portobello Green is often abandoned and was recently the subject of a Police Dispersal Order because of problems of antisocial behaviour and street drinking."
The trust also moved to allay fears that the number of vintage traders would fall: "There are around 160 stalls in the vintage market. There are no proposals to diminish the number of stalls or traders. We want to provide a better trading environment and support facilities, which would hopefully lead to an increase in stalls.
"There are currently 26 units in Portobello Green Arcade and offices above. While it is early stages in the proposal, we would hope to be able to accommodate between 60 and 70 new units in the new scheme."
Consultation has begun, and the trust said: "We are at the beginning of the design consultation, building on the previous consultation for the Westway Supplementary Planning Document in 2012. We do not have a fixed date for submission of a planning application."
Would the changes mean higher rents? "Stall rents are set by the market operators and Royal Borough of Kensington and Chelsea, rather than the trust, and will obviously be subject to market forces."