Exporting Silicon Valley

The BBC's Dave Lee in California assesses the changing fortunes of Silicon Valley's tech giants and Nolan Bushnell, the legendary founder of Atari, explains why he's getting back into computer games. Ed Butler reports on Ghana's tech start-up scene and Leah Busque from TaskRabbit explains why the struggles of some gig economy companies might turn out to be a good thing. Special guest Gerard Grech from Tech City UK joins Rory Cellan-Jones in the studio to give his views on what makes a successful tech start-up hub.

(Photo: A Facebook 'like' symbol on an Apple laptop, Credit: Getty Images)