A groundbreaking £15m private finance initiative project at London’s Pimlico School hangs in the balance this week after governors withdrew their support.

The board voted to oppose the plan to redevelop the school and build flats on another part of the site. The proposals were put forward by the St George Square Partnership, a Kier-led consortium that includes Costain and Tilbury Douglas.

Westminster council issued a statement on Tuesday saying that a meeting of the council’s PFI subcommittee would be convened to consider the matter.

The governors’ decision comes after a Westminster planning committee voted on 18 February to reject the height, bulk and design of the school buildings, which were designed by architect Ellis Williams. The decision overruled the planning officer’s recommendations.

John Tibbetts, general manager of the St George’s Square Partnership, said: “We are still waiting to hear formally what was resolved at the planning committee. We intend to submit revised designs for planning permission in four to six weeks.” Pat Leon, chair of the board of governors, said a group would be set up to come up with ideas based on a 1995 report by consultant CarlBro.