A former employee of London-based political consulting firm Cambridge Analytica has said the company "absolutely" planted fake news.

Christopher Wylie said Cambridge Analytica used the personal data of 50 million Facebook members to influence the US presidential election in 2016.

Facebook said Aleksandr Kogan, who created the personality app from which the data was harvested, has agreed to be audited, but Mr Wylie - who made the claims about the way the data was gathered and used - has declined.

Cambridge Analytica denies any wrongdoing.