Where there’s space, this has already been done. Unfortunately for many lines there simply isn’t space.

Just about every abandoned station, elevator shaft, and maintenance tunnel on the network is already fitted out with huge fans where possible.

TfL also runs a semi-continuous works project that looks a custom and novel one-off cooling solutions that can be retrofitted into whatever space is left. Including complicated hydronic systems that pump around huge quantities of water where the infrastructure allows for it.