Zuckerberg classmate launches attack in front of MPs

Mr Greenspan told MPs he had developed a portal for students, to unite various campuses at Harvard, called houseSYSTEM but also referred to as The Facebook, in 2003.

Damian Collins, who chairs the committee, has frequently called on Mr Zuckerberg to come to Parliament to answer questions about how Facebook operates - but he has refused.

To the sub-committee, he described Facebook as a "black box", claiming advertisers were "in the dark" about how effective their campaigns on the platform were and how many real users they were actually reaching.