Joseph Williamson

Joseph Williamson was a philanthropist in early-19th century Liverpool. He had a mysterious awareness of the chaotic state of time and the universe in connection to the Flux crisis, and indeed, seemed capable of wandering across different times and places.

Biography
In 1820, he funded and supervised the digging of tunnels (later known as the Williamson 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)

Williamson somehow found himself wandering in the corridors of the Temple of Atropos on the planet Time. There, he stumbled upon Yasmin Khan, who had been transported there after being swallowed by the Flux after it came into contact with vortex energy. The two exchanged a few words, with Yasmin informing him that from her perspective the year was much different from 1820. Williamson found this interesting, but soon wandered off, refusing to explain his presence or to let Yasmin follow her; he claimed people following him was always "to no avail", in his experience. (TV: War of the Sontarans)

Whilst in the midst of a time storm after taking the place of a broken Mouri in the Temple of Atropos, Dan Lewis found himself with Williamson in a tunnel. Williamson was using an alien weapon to shoot at an unseen assailant and helped Dan evade particles of the Time Force. (TV: Once, Upon Time)

Legacy
In the 21st century, his tunnels still existed and were called Williamson Tunnels in his name. (TV: The Halloween Apocalypse)

Behind the scenes
In the real world, the tunnels' true purpose is unclear, and is the subject of much academic speculation.