The Bluewater shopping centre in Kent, built in a former quarry, is about to become the UK's biggest.
Lend Lease, the Australian property group that owns the centre, is applying for planning permission for a 375,000 sq ft extension to the 1.6 million sq ft mega-mall.
The added space means it will shadow Westfield's two shopping centres in London and Gateshead's Metro Centre.
Bluewater was opened in 1999 and was the first UK mall to create separate areas for different uses.
Public consultation for the extension begins in September and a full application will be submitted later this year.
Bluewater has been trading well through the recession, with June sales up 6 per cent compared with the same month last year. The centre has been keen to attract new brands and in the first six months of 2012 signed up 10 newcomers including the gourmet burger restaurant Byron and the US ice cream brand Pinkberry's.
Lend Lease is working on a number of schemes in the UK including the redevelopment of Elephant and Castle and the Hydro Arena in Glasgow. The outline plans for the Bluewater extension were made public yesterday by Dartford Council.