In an exclusive interview for Radio 4's World at One, Sir Paul McCartney tells Sarah Montague how his 'Meat Free Monday' campaign came about, shares his thoughts on young climate change activists, and his unreleased record of Christmas carols, made just for his family. He also talks about appearing at Glastonbury in 2020.

(Photo: Sir Paul McCartney, with presenter Sarah Montague
Credit: Sir Paul McCartney)