The pledge is written into the planning application submitted to Westminster Council by developers Native Land, but it is not clear whether the gallery space will be offered to those dealers faced with moving out of the existing galleries.
One dealer told ATG last week that he was "as much in the dark as anybody" over the plan and had heard very little from Native Land, the owner of the site, between 29-30 Old Burlington Street and 22-27 Cork Street (where the galleries are currently based).
With his lease up in June, James Mayor of The Mayor Gallery says he has heard nothing about either a lease extension or the possibility of a place in any new arcade.
The planning application was only listed by Westminster council on February 18 (ref 13/01715/FULL). It involves "demolition of the existing building and construction of a new building comprising nine floors above ground and three basement levels, including retail (Class A1) (of which a minimum of 994m2 GIA shall be occupied by Art Galleries)" and also "a publicly accessible arcade at ground floor level".
On their website, Native Land chief executive Alasdair Nicholls said: "We expect 30 Old Burlington Street to become the most sought-after development in Mayfair. It will satisfy international and domestic demand for new-build accommodation in an area boasting London's finest restaurants, shopping and galleries." The statement added that they had been "consulting on its plans since September" ahead of the application.
But Mr Mayor said: "We are not really told anything. We are much in the dark as anybody. I don't understand what is going on. Some people have been offered an extension to their lease to the end of the year, but I haven't heard a thing."
He said a request for space in the new development had not been answered, and added: "I have no more idea of what's happening than anybody else, it is in the hands of the planners and we are contesting it."
Although Native Land have committed to the art gallery space in writing, Class A1 has no specific provision for such use - it is for "shops, retail warehouses, hairdressers, undertakers, travel and ticket agencies, post offices (but not sorting offices), pet shops, sandwich bars, showrooms, domestic hire shops, dry cleaners, funeral directors and internet cafes".
ATG asked Native Land how they would ensure that the space would definitely be used by art galleries - would they be offered reduced rents, for instance - but had yet to receive a response as we went to press.
When news of the proposed development first broke last summer, campaigners launched Save Cork Street to protect the galleries, and an online petition had attracted more than 13,000 signatures by last week.
One suggestion is to create a Special Policy Area for Cork Street to safeguard the art and antiques galleries deemed synonymous with the area - as has happened with tailors on Savile Row and the private clubs and art galleries in St James's.
In October last year it also emerged that five galleries at 5-9 Cork Street faced relocation because of a separate scheme - meaning that half the 22 galleries in the street will have to move if the two redevelopments are approved.