Westminster council has unanimously approved Foster + Partners’ designs for a refurbishment of a listed townhouse site on St James’s Square as the head office of a science institue set up by the world’s sixth richest man.

The Ellison Institute of Technology (EIT) is an advanced research body set up by Larry Ellison, the former chief executive of software company Oracle Corporation and a close ally of Donald Trump.

EIT, which describes itself as multi-disciplinary science institute, is currently building a £300m science research facility in Oxford that has been designed by Fosters with the first phase being built by Laing O’Rourke.

The organisation’s London headquarters will transform two grade II and grade II*-listed buildings at 11-12 St James’s Square and rebuild an extension to the rear of the site that was completed in 1990.

The scheme would retrofit the existing historic buildings and knock down the rear extension, adding new lifts, showers, cycle storage space, new glazed facades and terraces and reinstating a historic garden at ground level.

The job, which has been described as “very high spec”, is understood to have a price tag of around £120m.

Other firms working on the plan, which was sent in to Westminster city council in January, include development manager Edit, planning consultant Avison Young, heritage consultant Donald Insall Associates and project manager Ridge.

Building Design understands Sir Robert McAlpine is due to build the scheme after beating Multiplex for the main contractor role.