We reported last year that housing association Peabody had sold the triangular site bounded by Borough Road, Newington Causeway and the Thameslink rail line to Berkeley Homes.
As well as Mercato Metropolitano, the site includes the Institute of Optometry as well as a Baptist chapel and the London School of Musical Theatre.
Southwark Council's new planning policy document – the New Southwark Plan – is based on an assessment of the site's development capacity as being 438 new homes.
Berkeley Homes is currently putting an argument to the Government-appointed planning inspectors who will rule on the soundness of the council's plan that the minimum number of homes to be built at the Borough Triangle should be in the range of 750 to 1,000.
This compares to Peabody's previous intention to build between 600 and 700 homes on the site in buildings up to 39 storeys.
A written statement submitted to the examination-in-public by consultants Lichfields on behalf of Berkeley Homes argues that the Borough Triangle "provides an obvious opportunity to deliver a significant proportion" of the 5,000 new homes in the Elephant & Castle opportunity area foreseen by Sadiq Khan's recently approved London Plan.