Chancellor George Osborne also attended the launch and said he hoped other firms would follow Facebook and set up shop in the capital, as the Government strives to establish the UK as a world technology leader.
"We are being quite determined in our effort to bring over the biggest technology companies...by ensuring you can find in this city and country the type of talented people they need to be your engineers, sales force and the like," he said.
As an example of the work the Government is doing to encourage this, Osborne flagged its decision to overhaul the school ICT curriculum and the incentives on offer to people to retrain as computer science teachers.
"There is a huge and fast growing demand for the type of [tech] skills you need...so instead of pupils just learning how to operate Excel and Powerpoint, they're also being taught how to write code and build apps," said Osborne.
"We're also hiring more teachers to teach these kinds of programming skills...[so]if you're a computer science graduate that becomes a teacher you will get a government bursary of 9,000 to encourage you to do that."
