Telegram is the fifth most downloaded app on the planet, with almost a billion users worldwide. More than six million people in the UK have it on their phones, but the social media platform is also popular with criminals and extremists. Telegram has been called a one-stop shop for crime and now its billionaire owner is under investigation by French police. They have accused Pavel Durov of complicity in drug dealing, fraud and the sharing of child sexual abuse images on Telegram. Reporter Bronagh Munro investigates how the app can spread harmful and dangerous content.
