Ian Simpson Architects and de Rijke Marsh Morgan (dRMM) have been chosen to design the first phase of the £5.5bn Battersea Power Station development.

Treasury Holdings UK, the developer behind the scheme, has confirmed that Rafael Viñoly will remain as architect-in-chief and will oversee the delivery of the site's overall regeneration. The first phase of the scheme will comprise more than 1 million sq ft (92,903sq m) of new building space located in two blocks to the west of Battersea Power Station.

Ian Simpson Architects will be responsible for designing the larger of the two blocks, while dRMM will lead the design of a residential block on the western boundary of the site. The appointment of the design firms for the first stage comes days after the Battersea Power Station redevelopment cleared its final planning hurdle.

Work is due to start on the first phase in summer 2012.