"It's only if centre ground, and the centre left particularly, are changemakers not guardians of the status quo, that we'll succeed. Otherwise... the person who comes along and represents change will take the laurels."

Is populism just about being popular or is it a matter of saying what the public want to hear even if a politician is not sure how to deliver it?

Former UK Prime Minister Tony Blair joins Jon Sopel to talk about populism, globalisation, social media and centrist politics.

Also on the programme: the fake story 'pizzagate', and Anthony Zurcher on how - and why - Donald Trump uses Twitter.