The encrypted messaging app Telegram is haunted by a single question - if it really is as secure as it claims to be, why does Vladimir Putin allow it to be used in Russia?

And should Russian dissidents, independent journalists and Ukrainian soldiers use this Wild West of an app, where you can find everything from porn to drugs to faked propaganda videos?

Answering those questions takes Helen on a journey that begins with a young Russian entrepreneur throwing 5,000 rouble notes off a balcony, folded like paper aeroplanes, and finishes with him in exile in Dubai, rich beyond his wildest dreams. But what does Pavel Durov, the founder of Telegram, really believe?

Producer: Tom Pooley Assistant Producer: Orla O'Brien Sound Design: Louis Blatherwick Editor: Craig Templeton Smith Original Music: Coach Conrad

A Tempo & Talker production for BBC Radio 4