These formed an integral part of the corridor asylum with many thoroughfares snaking through the wards themselves. Because this caused disruption to the patients, the corridor design became outmoded and was eventually abandoned (and there was the small issue that corridor asylums couldn’t scale up to the huge sizes of buildings envisioned by the architects and Asylum Board).

Other main arterial routes through corridor asylums were small and narrow, and they must’ve been congested and difficult to navigate (especially with an infirm patient in a wheelchair or a bed).

By the time of Severalls, the echelon pattern was proven and successful. Arterial corridors were wide and airy; and each ward was serviced by its own corridor and was additionally joined to its neighbours.

Originally the corridors at Severalls had no windows or doors and were little more than covered walkways. The female staff used to run screaming down the passageways in the twilight as bats flew down the endless corridors. Eventually they installed windows.