A heritage plaque has been installed inside an HS2 tunnel 40 metres below London, marking the point where the new high-speed railway passes beneath the tomb of one of Britain’s most famous engineering families. The invention was subsequently used to excavate the Thames Tunnel beneath the river, work on which began at the end of 1825. More than two centuries later, the tunnel-boring machines digging the HS2 railway tunnels use modern tunnelling shields based on the same fundamental principle pioneered by Brunel. Considered an exceptionally ambitious and dangerous undertaking when it was built, the tunnel was the longest railway tunnel in the world when it opened and remains one of Brunel’s best-known engineering achievements. Mark Wild, Fellow of the Royal Academy of Engineering and HS2’s CEO, said: “The significance of the achievements of both Sir Marc and Isambard Brunel in engineering cannot be under played.