K5 was a metal-faced plywood construction introduced in 1934 and designed to be assembled and dismantled and used at exhibitions.

It is not known how many were produced, and there is little evidence they ever reached more than prototype stage.

A fully detailed replica (constructed using the original drawings) can be seen at The Avoncroft Museum (Bromsgrove, Worcestershire), as part of the National Telephone Kiosk Collection.