Whistleblower gives behind-the-scenes look at Trump campaign

Chris Wylie can't prove the work he did for Cambridge Analytica helped Donald Trump win the 2016 presidential election, but he thinks he has pretty good evidence.

While working for the political consulting company from 2013 to 2015, Wylie's team spoke to Americans in focus groups to identify deep-seated concerns. Then they tested ways to tap into those fears through social media. The slogans they developed later became the catchphrases of the Trump campaign, he says.

"My ears perked up when I started hearing some of these things like 'drain the swamp' or 'build the wall' or 'the deep state' because these were all narratives that had come out from the research that we were doing," Wylie told an audience at London's Frontline Club on Tuesday night.

The 28-year-old Canadian is at the center of allegations that Cambridge Analytica improperly used data from over 50 million Facebook users to identify voters who might be sympathetic to Trump's message and target them with social media messages. In stories by the New York Times and Britain's Guardian newspaper over the past week, he explained how he created the psychological warfare tools for Steve Bannon, the right-wing former banker who later became Trump's chief strategist.

At the wide-ranging talk in London, Wylie described in further detail how the company worked and Bannon's central role in shaping it.

Wylie says Facebook data collected by a Cambridge University researcher was used as part of a project commissioned by Cambridge Analytica. The firm says none of the Facebook data was used in the work it did for the Trump campaign. Facebook has suspended Wylie and Cambridge Analytica while it investigates the allegations.

Wylie was in his early 20s and had been working on a PhD in fashion trend forecasting when he went to work for defense and intelligence contractor SCL Group, which later teamed with Bannon to create Cambridge Analytica. Alexander Nix, CEO of Cambridge Analytica, offered the "freedom to explore the research I really wanted to do," Wylie said.

Bannon, unlike other clients, wasn't impressed by Nix's posh pedigree or fancy meals at exclusive London restaurants, so they closed the deal by setting up an office in Cambridge to align the new company with the history and prestige of Cambridge University.

"We presented ourselves as much more academic. Not to say that we weren't academic, but we needed to curate our presentation so we created this fake office ... beside the university to make it look like this is our Cambridge site. This is our Potemkin Cambridge office.' "

But the data was real, and Cambridge Analytica used that information, together with insights gained from focus groups with angry Americans, to identify issues and target voters. Bannon supplied the ideological focus of wanting to remake America and billionaire Robert Mercer provided the money. Neither Bannon nor Mercer has publicly commented since the allegations emerged.

The work was a mix of old-fashioned canvassing and the use of millions of data points to test out slogans and push them onto social media.

"We would just go chat with people. We would go sit in their living rooms. We would look at how they live," said Wylie.

He said Cambridge Analytica had an advantage in listening to Americans because as foreigners they may have had fewer preconceptions.

"One of the things that started to emerge was that we literally heard these sort of narratives about Washington as something that was, like, gross and disgusting, that was dirty," Wylie said.

So his team tested the phrase "drain that swamp" to see if people would respond to it on social media. After all, they had access to the data of millions of Facebook users without their knowledge.

And people responded. Through the internet and Trump's speeches, the slogan became one of the campaign's most identifiable soundbites.

Perhaps it is the idea of building a wall along the Mexican border that best illustrates Wylie's work for Cambridge Analytica.

Bannon, Wylie said, was obsessed with the idea of separating the U.S. from the rest of the world so the country can rediscover itself. Trump's campaign for a wall along the Mexican border is not really about stopping immigrants, Wylie said.

"It's to embody separation," he said. "If you can embody that separation and you can further distance in the minds of Americans us here in America and them elsewhere, even if it is just across a river, or just across a desert, then you have won that culture war."