The Thames Tunnel, an 11m wide, 6m high and 396m long tunnel cuts 23m under the river Thames when measured at high tide. It is the first known tunnel to be excavated under a navigable river. And most critically for today’s episode it is the first use of a tunnelling shield, which some 200 years after its original inception is today one of the most impressive achievements of engineering.

In this episode we explore the lives of the men behind the shield. The two men who first patented an idea that would be gradually built upon, revised, honed and improved to become the modern Tunnel Boring Machine. One of those men you will be most familiar with as the father of Isambard Kingdom Brunel. Marc Brunel was the engineer for the Thames Tunnel and worked with his son Isambard to build the tunnel. The second man, who patented the Tunnelling Shield alongside Marc Brunel was 10th Earl of Dundonald and head of the Chillean Navy. A battle hardy ships captain and an expelled Member of Parliament, he is nick named the Wolf of the Sea by Napolean and the Metalic Lord by the Spanish. He himself went by the name Lord Cochrane.