Put out to consultation this weekend (8 March) by the Hadley Property Group, early designs for the 2,000-home proposals include the substantial remodelling of the 100,000m, 23-year-old mega-office next to the A4 Great West Road in Brentford.It is understood Studio Egret West will strip the 18-storey roadside landmark back to its core, retaining the basement and parts of the substructure. Steel from the existing building will be reused to build an extension on the top.The 300 million office block, designed by Hillier with RHWL and Swanke Hayden Connell, was the biggest single commercial development in the UK when it was opened in 2002 by then-prime minister Tony Blair.AdvertisementGlaxoSmithKline (GSK) sold the 5.4ha site, known as 980 Great West Road, to Hadley in 2021 and announced its plans to fully vacate the building by the end of last year, relocating all staff to a new Apt-designed building in Londons New Oxford Street. Source:Google Earth GSKs now-vacant former headquarters in BrentfordThe masterplan, led by Haworth Tompkins, creates around 17 different buildings and redevelops the site as a new mixed-use neighbourhood for Brentford, including a minimum of 35 per cent affordable and student housing. There are also plans for around 20,000m of commercial space.The developer said it wanted to knit the site back into Brentford, reconnecting the communities to the north of Great West Road with Brentford town centre, and would include new pedestrian and cycle-friendly routes, public spaces and amenities, commercial and employment space.The consultation boards show how spaces under the M4 would be opened up, creating a public destination for multigenerational activities and a new entrance into Boston Manor Park.Each of the practices has been given several different plots to work on.AdvertisementThe project team also includes sustainability consultant Buro Happold, landscape architect McGregor Coxall, Walsh engineers and Turley.Hadley has already carried out extensive engagement on the designs with the London Borough of Hounslow and the Greater London Authority (GLA) planning teams, as well as local residents.Submission of a planning application is expected this autumn.Aerial sketch of plans for GSK site the main office block will become a new 20-storey residential tower