WhatsApp co-founder Jan Koum

Jan Koum, who sold the online messaging service WhatsApp to Facebook for $19 billion in 2014, said it was time to ‘move on’.

Koum is leaving both the WhatsApp and Facebook boards after disputes over issues including strategy and efforts to use WhatsApp data and ‘weaken its encryption’.

Facebook has faced scrutiny since the Cambridge Analytica scandal, in which data from up to 87 million members was improperly accessed.