Just how big is London's science and tech sector? Tech Map London gives an idea.
The site, commissioned by the Mayor, displays various charts, maps and graphs to give a notion of the magnitude of this city's digital businesses. The main data source is Companies House, which holds information on addresses, employee numbers and turnover.
Headline figures: London employs around 700,000 people in science and tech businesses, comprising some 94,000 firms. The sector has a cumulative turnover of £153 billion. Perhaps surprisingly (though not when you think about it), the top boroughs for the sector are Westminster and Camden, plus the City of London. The much vaunted tech hub of Shoreditch figures less prominently, perhaps because it is smeared among Hackney, Islington, Tower Hamlets and the City.
It's impressive stuff, but should be considered impressionistic rather than authoritative. For smaller companies, turnover and employee number is often estimated. The estimates are significantly wide of the mark for Londonist and other companies in our sphere, and we can assume this is a common problem across the map. Whether this averages out for the big picture, we're not sure. Just treat the data with caution.
Explore Tech Map London here.