Isambard Kingdom Brunel

Isambard Kingdom Brunel was an engineer and — in the words of the Eighth Doctor — "the man who built the modern world".

Brunel designed the Clifton Suspension Bridge, the SS Great Britain, the Thames Tunnel, the Tamar Bridge and Paddington station. He also made significant contributions to the Great Western Railway.

In 1843, the Eighth Doctor, Fitz Kreiner and Anji Kapoor met Brunel in a timeline created when the mysterious Eternines attempted to alter history, draining energy from Earth to sustain their own world. Brunel sacrificed himself to give the Doctor to chance to undo this new history, erasing all memory of his encounter with the Doctor. (PROSE: Reckless Engineering)

An earlier incarnation of the Doctor had met Brunel at some point and acquired his business card, which he kept in his address book. (TV: The Two Doctors)