They have previously hit out at developers and property owners who they feel are strongly in favour of seven-days-a-week chain stores and high-end boutiques rather than the traditional Saturday antiques trade, and the last day of the Gallery at 287-289 Westbourne Grove on May 26 will be the latest blow.
But in this case the premises are believed to be family-owned rather than a large landlord with several properties, and Marion Gettleson, the Portobello antiques trader who has run a Facebook campaign called Save the Portobello Road Market, said it was sad and it seemed to be more "the end of an era".
She pointed out that the number of empty shops along the western end of Westbourne Grove is "utterly amazing", and although there is no shortage of people visiting the area there is a shortage of those spending money.
It leaves Burton as the last antiques arcade in Westbourne Grove, with some street stalls on Saturdays.
The Gallery opened in 1987 and has dealt with high-quality Oriental and European antiques. Maria Nieves Villacampa-Ascaso, one of the founder stand holders, said most of the 16 dealers will "relocate to new stands within Portobello Antiques Market".
She added: "It will be with great sadness that I'll close my stand in the gallery. I have enjoyed the ambience, and the true cosmopolitan bunch of dealers, collectors and tourists that has come in to say hello."
Portobello Antique Dealers' Association chairman Costas Kleanthous told ATG that he was very sorry to see the gallery go, but understood it was for family reasons. "It's a shame because there are some really very good dealers in there and I'm not sure, as yet, what will happen to all of them," he said.
A planning application for 287-289 Westbourne Grove submitted to Kensington and Chelsea council planning department was approved in January this year, including alterations to the shopfront. A floorplan shown as part of that application has the separate stalls inside replaced by single commercial units. The applicant is listed as Mr J Harding.
ATG asked the Harding family for a comment but had not received a reply at the time of going to press.
The closure comes hot on the heels of a successful appeal paving the way for seven-day trading at the Admiral Vernon Arcade in Portobello, which left antiques traders who trade on Saturdays concerned about the implications.