The untold story of the hidden places across Britainthat have slipped through the fingers of history.

Dr Matthew Green is a historian, writer and broadcaster with a doctorate from Oxford University. He has appeared in documentaries on the BBC, ITV and Channel 4, and has written historical features for the Guardian and Financial Times. He is the founder of Unreal City Audio, which produces immersive tours of London as live events, podcasts and apps. He is the author of London: A Travel Guide Through Time and Shadowlands: A Journey Through Lost Britain.