Last week, Mike Schroepfer, Facebook's chief technology officer, appeared before the Digital, Culture, Media and Sport Committee and according to the committee's chair, Damian Collins, he didn't do a very good job. The committee was left with nearly 40 unanswered questions, which led it to re-request an appearance from the CEO himself. "As you may have seen from my press statement, the committee feels that the evidence lacked many of the important details that we need," Collins said in his letter to Facebook UK Head of Public Policy Rebecca Stimson. "We therefore re-state our invitation to Mark Zuckerberg."

In his letter, Collins included the list of questions that remain open and they stand in stark contrast to those presented to Zuckerberg by the US Senate and House committees earlier this month. While Congressional leaders asked the CEO many of the same questions repeatedly and inquired about rather basic concepts, such as how Facebook makes money, the UK committee's questions dive into audits of third-party developers, the legalities of storing non-Facebook users' data and dark ads. Zuckerberg's mediocre performance in the US may shed light on why he's so hesitant to testify before a more tech-savvy group of politicians.

The UK committee has asked for responses to its questions and its invitation by May 11th and it would like to host the CEO by May 24th. "We hope that he will respond positively to our request, but if not, the committee will resolve to issue a formal summons for him to appear when he is next in the UK," wrote Collins.