A new tech and creative hub will be built on a 62-acre site in the Royal Docks area of east London.
The land, which includes the Millennium Mills, is owned by the Greater London Authority and is the largest undeveloped site at the docks.
A cluster of purpose-built centres for product innovation will be built there as well as a school, cafes, restaurants, galleries and public spaces.
Work began earlier this year, following a £12m government investment secured by the mayor of London, to demolish parts of the interior of the former flour factory and rid it of asbestos in order to fast track redevelopment.
That work means the site will be ready to welcome the next generation of start-up business by 2017.
Boris Johnson said: "By breathing new life into this wonderful old flour mill we can rejuvenate this area of east London and contribute some serious dough to the capital's economy.
"Silvertown Quays will provide thousands of new jobs and thousands of much-needed new homes and facilities for local people as we return the area to its former glory."
The plans have been approved by the Mayor of London's office, it was announced.
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