Major revamp planned for Westminster's Millbank Tower

John McAslan & Partners is preparing to submit plans to extend Millbank Tower by three storeys and entirely re-glaze the grade II-listed London landmark.

The project would convert the 1963 riverside office building, which has been home to both the Labour and Conservative parties and the UN, into flats with the new floors earmarked for penthouses. The northern podium - known as the Y building - would also gain an extra three storeys.

A three-storey cultural space is proposed for the southern end of the podium. It could house a new national Holocaust memorial and learning centre. The government-appointed Holocaust Commission is due to announce the chosen location next year. If Millbank is selected an international architectural competition would be held for its design.

JMP was appointed by Basio Holdings to repurpose the 32-storey complex, designed by Ronald Ward & Partners. It will contain 220 flats and a 200-room hotel as well as more public uses such as a bar on the new 34^th floor and a cafe in the extruded podium.

The glazing would be replaced with a more thermally efficient version, the appearance of which would be “in keeping with the original grade II listed façade”, said the architect.

An amphitheatre auditorium would be built outside, linked to the indoor cultural spaces.

The proposals, currently out for consultation, are due to be submitted to Westminster council in August. Work would not begin before 2019.

It is not the only London office tower becoming residential. Richard Seifert’s Centre Point is currently being converted into flats by Rick Mather Architects and Conran & Partners.