BBC Sounds, music radio podcasts.

Hello, I'm Tina Dehealy.

Welcome to Beyond Today from BBC Radio 4,

where we ask one big question about one big story.

Today, how do you track extremists online?

When I was a kid,

when I was a kid I was really fascinated by tornadoes by the speed and the force of them.

Julia Ebner monitors extremist movements across the UK, Europe and America.

It's not that dissimilar to be chasing extremists in a sense,

because you also really have to keep...

Like storms, extremists are fast, destructive, and can change direction at any time.

Julia tracks them during her day job as a counter-terrorism expert advising governments and

tech companies on how to respond to extremist activities.

Two years ago, she decided to go under cover to find out exactly what drives people into these groups. She ended up meeting

white supremacist in a Mayfair pub. She befriended female misogynists online and

even travel to a Nazi rock festival on the German

Polish border. Judy's written about her disturbing encounters in a new book

Going Dark the secret social lives of extremists.

I wanted to see what it really is that drives individuals into extremist movements

because it felt a bit like I was hitting a wall doing some of the research, but it didn't feel

like I could get a better sense of what the human dimensions are, what it is that keeps people

within those really extreme movements and so by going under cover was able to speak directly to those people and to really understand and grasp what also group dynamics look like, what the recruitment procedures look

...