In this bumper edition of the podcast we interview three of the world's leading artists, all of whom have shows timed to coincide with the Frieze art fairs: Ai Weiwei at Lisson Gallery, Mark Bradford at Hauser & Wirth and Peter Doig at Michael Werner Gallery. We also get all the latest news of sales and trends at the Frieze fairs from Melanie Gerlis, as another Brexit deadline approaches. And Hettie Judah tells us about her new book, Art London, billed as "a guide to places, artists and events" across the city.