Jaan Tallinn, the co-founder of technology giant Skype, which is now owned by Microsoft, has revealed that he is working on a new project.

Having successfully helped to save long-distance relationships with his video phone call platform, he is now trying to save the world.

The Estonian entrepreneur is a pioneer in a movement known as “effective altruism”, defined as “compassion guided by data and reason”. He has spent a year working out how blockchain – the technology on which the cryptocurrency Bitcoin is based – can be used to solve humanity’s biggest problems, from crime and corruption to deforestation and over-fishing.