Stephen Sackur speaks to Green Party of England and Wales politician Caroline Lucas. She’s the party’s only Westminster MP, but she’s decided to quit. Is that because putting the planet first is never going to be a pathway to power?

Stephen Sackur speaks to the acclaimed Israeli historian and author Yuval Noah Harari. Having given us an explanation of the success of humankind in his book Sapiens, he’s now in darker territory. From Israel to the United States, he says democracy is in danger. Are humans losing the ability to...