Christopher Wylie is a 30-year-old Canadian data specialist who moved to London a few years back, started working in political campaigns, and then became deeply involved in two of the biggest political events of his lifetime: the Brexit referendum and the election of Donald Trump. He worked for Cambridge Analytica, the company that was caught harvesting data from millions of Facebook accounts and using it for political advertising purposes. We’d been warned for years it could happen, and it was the first time we saw how data could be used and weaponised to win an election. This is that story.