Joseph Williamson was a philanthropist from early-19th century Liverpool.
In 1820, he funded and supervised the digging of tunnels whose purpose was unclear to his contemporaries, although they did provide employment to the poor. He seemed to have some inkling of a great upcoming cataclysm which would somehow justify the tunnels, although he only spoke of it cryptically and evasively. (TV: The Halloween Apocalypse)
Behind the scenes
In the real world, these tunnels are now called the Williamson Tunnels. Their true purpose is unclear, and is the subject of much academic speculation.