London walk #BBCWeekend @BBCworldservice radio with @Goblinmerchant

World War II evacuation shelters, secret government bunkers, 'ghost' tube stations; and long-lost rivers, that's what lurks underneath the enormous sprawling city of London if you know where to look. More importantly you have to find a way inside some of these places. Dr Bradley L Garrett , is a geographer from the University of Oxford. He's a former member of the once notorious and now defunct London Consolidation Crew (LCC), a team of urban explorers whose missions into these hidden places are documented in a new book called #SubterraneanLondon: Cracking the Capital. Dee Sebastian caught up with Bradley on one innocuous London street.