Although work has been going on for some time to prepare the Docklands’ iconic Millennium Mills for a 21st century purpose, the vision has finally been cleared by Mayor of London Boris Johnson.

The derelict mill, which once made dog biscuits, will be converted into a vast hub for startup and tech business, surrounded by shops and homes and linked to Crossrail via a new ground-level bridge across the Royal Docks. Permission was given by Newham Council in April 2015.

A cluster of purpose built centres for product innovation will be built there as well as a school, cafes, restaurants, galleries and public spaces.

The development of Millennium Mills by Silvertown Partnership, taking an old flour mill and making tech city style flexible units

The £3.5billion plan is to create 20,000 new jobs on five million square feet of business space alongside 3,000 new homes on the 62-acre Silvertown Quays site.

The scheme, along with the Royal Wharf and the ABP development represent a multi-billion-pound transformation of the derelict docks into a thriving community. They will join Excel, the Crystal and UEL as waterside showpieces connected by the London City Airport, DLR and Crossrail.

Mr 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.”

Brand Pavilions will showcase new consumer products at Silvertown Quays

The mills are not only vast but extraordinarily awkward. Different warehouses of different sizes were developed over the years with skyline busting Silo D still presenting a conundrum for designers.

It was with this challenge in mind – and the presence of asbestos – that prompted a £12million programme of works to lay the groundwork and fast-track development. As a result the site should be ready by 2017, say developers.

Redevelopment forms the centrepiece of a wider £3.5billion project, led by the GLA’s development partners the Silvertown Partnership. It is anticipated the redevelopment will attract 13million visitors a year to brand pavilions and other attractions and will contribute £260million each year to London’s economy.

Sir Stuart Lipton, who leads The Silvertown Partnership, said: “This is an important milestone for Silvertown. [This decision] ensures that this derelict and forgotten piece of east London is reinvented as a new creative hub for our capital – drawing the world’s best creative talent, most ambitious start-ups and most innovative businesses.”

Plans are also being developed to build the Silvertown Tunnel to connect the Royal Docks and Greenwich Peninsula, which if approved could become operational by 2023.

Redundant machinery inside the Millennium Mills