Updated

The whistleblower at the heart of the Facebook privacy scandal is set to testify before British lawmakers investigating the increasing rise of fake news.

Christopher Wylie has alleged that Cambridge Analytica harvested details of 50 million Facebook users and used the material in U.S. President Donald Trump's 2016 election campaign. It is alleged the material made it possible to micro-target users with campaign material.

At a news conference on Monday on a linked issue, Wylie declined to answer questions about whether the data was also used in Britain by the campaign to leave the European Union. He said he would discuss the matter when he spoke to lawmakers from Parliament's media committee on Tuesday.