Hi, Namulanta Combo here, and I'm excited to tell you that my award-winning podcast, Dear Daughter, is back for a second season, and it's available now.

Find out more at the end of this podcast. I've come to the shard skyscraper in central London, the tallest building in the capital,

72 stories, bursting into the sky with its glass panels that resemble a church spire.

It's a place popular for business meetings, and I've come here to catch up with a tech boss

who has flown in from his HQ in Geneva.

This is the main entrance.

Think of big tech companies and your first thought might be Silicon Valley, but Europe has some too.

One is Proton, a company best known for its secure encrypted email service, Proton Mail.

Proton was founded in Switzerland in 2014, and now more than 100 million people have accounts with them.

And they have more than 400 employees globally. Not bad for a

company set up by a particle physicist based at CERN, whose CV up to that point was an academia,

not business. In some sense, being naive, being a scientist, you know, caring about mission

and being obsessed with technology, That is something that maybe allows,

I think, other scientists who are today working in businesses to somehow make decisions

that would not seem conventional or even logical. I'm Dougal Shaw and welcome to another

edition of Business Daily Meats on the BBC World Service.

This is where we bring you in-depth interviews with people in business from across the globe.

Today we're meeting Andy Yen, the founder and CEO of Proton.

He set up a tech company whose main product, Proton Mail,

seeks to rival other email services like Microsoft's Hotmail or Google's Gmail. Unlike those services, though, his email platform is encrypted, so the company cannot read the emails that pass

through its own servers. Proton makes money by charging a minority of its users for premium features.

If I look at Proton's business as a whole, what was our business model in 2014?

...