MPs tell Mark Zuckerberg to volunteer Cambridge Analytica evidence or face formal summons

• Facebook will answer all the questions [the government] has sent
• Facebook hopes those answers, together with oral evidence, will provide the Committee with the detail they require
• If [the government] has further questions at that point, then Facebook will work with it to give the information it needs

The warning shot from the government was fired by Damian Collins, the chair of the Digital Culture Media and Sport (DCMS) Committee.

The politician has penned a letter to Facebook saying he he was left unsatisfied by the responses provided by its chief technology officer Mike Schroepfer, who represented the social media company in parliament on Monday (30 April).

Schroepfer faced tough questioning over Facebook's handling of private user data, but DCMS said the evidence "lacked many of the important details that we need."

Collins stated in the letter: "We therefore re-state our invitation to Mark Zuckerberg. Following reports that he will be giving evidence to the European Parliament in May, we would like Mr Zuckerberg to come to London during his European trip. We would like the session here to take place by 24 May."

Collins went on to say that while Zuckerberg doesn't normally come under the jurisdiction of the UK parliament, he will do so the next time arrives in the UK.

"We hope that he will respond positively to our request," said the letter, "but if not the committee will resolve to issue a formal summons for him to appear when he is next in the UK."

This means that Zuckerberg could be issued a formal request to appear before MPs, as Rupert and James Murdoch did during the 2011 phone hacking committee.

A full copy of Collins' letter to Facebook can be seen below.

As well as issuing the demand, DCMS has issued a list containing dozens of questions it said Facebook had yet to give the UK government clarity on.

"Mr Schroepfer failed to answer fully on almost 40 separate points. This is especially disappointing to the Committee considering that in his testimony to [US] Congress Mark Zuckerberg also failed to give convincing answers to some questions," Collins said.

Questions the government believes Facebook to have failed to respond to include: queries around the number of digital platforms that track Facebook users, how many political ads are run on Facebook and how much money Facebook makes from fraudulent advertising.

MPs also want a firm answer on why Facebook transferred data responsibility for more than 1 billion users to Facebook US from Facebook Ireland just one month before the EU's General Data Protection Regulation (GDPR) is implemented.

Facebook has until 11 May to respond to both Collins' invitation and to issue the government with answers to the questions it outlined.

Since March, the tech behemoth has been embroiled in allegations that some 80 million of its users had their personal information harvested by data analysis firm Cambridge Analytica.

Since then, Zuckerberg has given evidence to US politicians, and Facebook has shut off third-party targeting on top of making other changes to how users view and change their privacy settings.