Facebook is under increasing pressure to explain how data collected on 50m users were exploited for political gain, following claims that data firm Cambridge Analytica used the leaked（leak n.泄漏;漏洞,裂缝vt.使渗漏,泄露vi.漏,渗;泄漏出去） information to help Donald Trump win the US presidency.

Politicians on both sides of the Atlantic are calling on the social network to reveal more information on how Cambridge Analytica, which has close ties to Steve Bannon, Mr Trump's former chief strategist, harvested data of mostly US voters.

British MP Damian Collins has asked Mark Zuckerberg, Facebook's chief executive ,to personally testify in an investigation into how the social network was also used in political campaigns including the Brexit referendum（n.公民投票权;外交官请示书(复数refcrendums或referenda)）. Mr Collins said it was time for Mr Zuckerbeig to “stop hiding behind his Facebook page”.

Mr Collins yesterday accused Alexander Nix, Cambridge Analytical chief executive，of “deliberately misleading” a committee hearing last month when he told parliament that his firm did not use any Facebook data. Mr Nix told the Financial Times at the weekend that he stood by his comments，despite a former employee turned whistleblower claiming he had evidence to the contrary. Mr Nix added： “We deleted our Facebook data at the time we were alerted to a possible contravention of Facebook data policies. w When asked why he did not disclose this to parliament（n.议会,国会）, he said： “They didn’t ask me that.”Amy Klobuchar, a Democratic senator from Minnesota, said Mr Zuckerberg needed to testify（vt. 证明，证实;作证） before the Senate as it was “clear these platforms can’t police themselves”.

So far only mid-level Facebook executives have defended the company since the revelations from Christopher Wylie, the Cambridge Analytica whistleblower（n.告发者;检举者）, were published in the New York Times and the Observer at the weekend. The social network executives said it was not a data breach because data had not been stolen or hacked.

The reports allege（vt.宣称,断言;提出......作为理由）that Cambridge Analytica was passed data（A is passed B A获得了B） collected by Global Science Research using a psychological survey app for research（用于研究的心理调查应用程序） purposes. It used this data, to create profiles（profile n.侧面;(书面的)描述） on the respondents（respondent n.受调查者） and their friends 9 which were used for political targeting（政治目标定向(调查你支持哪个党派)） without their consent（vi.同意;赞成;答应 n.同意;(意见等的)一致;赞成）. Facebook banned the data analytics company on Friday, three years after it first discovered it had broken its rules.