The former chief of the now-defunct firm Cambridge Analytica’s much-anticipated reappearance before MPs has begun with a row.
Digital, Culture, Media and Sport Committee chairman Damian Collins refused to allow Alexander Nix to make an opening statement.
Mr Nix “insisted” he be allowed to continue but each time he began, he was interrupted.
He is being quizzed as part of an inquiry into fake news.
The firm has been at the centre of a scandal after Facebook users’ personal data was obtained by the London-based political consultancy in breach of the social network’s rules.
Mr Nix was recalled to appear before the parliamentary inquiry following what Mr Collins described as “serious inconsistencies” between his original testimony and evidence received since.
Mr Nix previously gave evidence to the committee in February.
Cambridge Analytica, which announced it was closing in May, is accused of acquiring data from millions of Facebook users for use in political campaigns. The firm has denied any wrongdoing.
The company is now in administration and Mr Nix told MPs he had invested “millions of dollars” of his personal fortune in the last few months to pay the salaries and redundancies of staff.
He said he was “deeply embarrassed” about an undercover Channel 4 News report in which he discussed questionable methods – including sending “Ukrainian girls” to a candidate’s home – that might be used to gain clients.
Mr Nix said he had used “hyperbole”, admitting his claims had a “significant impact” on the firm he ran.
But he claimed that the footage had been edited to misrepresent the context of his words, and that Cambridge Analytica would not have engaged in such tactics itself.
The BBC has asked Channel 4 News to respond.