There's a plan to make cold things hot - and hot things cold - using the lost rivers that wind under cities like London. Sounds like magic? Is magic. SCIENCE MAGIC.

Just how *do* we warm ourselves up in winter without knackering the planet? Or should we just put a few more jumpers on and shiver? And what on Earth have we found in this pub's basement?

We investigate with Alice Bell from 10:10 and Louise Waters from Scene.

Sustainababble is your friendly environment podcast, out weekly. Theme music by the legendary Dicky Moore – @dickymoo. Sustainababble logo by the splendid Arthur Stovell.

Available on iTunes, Acast, Soundcloud & all those types of things, or at sustainababble.fish. Visit us at @thebabblewagon and at Facebook.com/sustainababble. Email us at hello@sustainababble.fish.