These tunnels were built in the 1970s as a hardened system to carry telecommunications. The tunnels linked Capital Exchange to the former Telephone House building. The west tunnel runs along Gorgie Drive to just past Stenhouse Drive, The south tunnel travels south east and then follows part of Gorgie Park Close and Appin Terrace before terminating near the junction of Colinton Road and Craiglockhart Terrace. Dark gray louvred ventilation shafts and emergency escape hatches can be found at intervals along the route. (e.g. junction of Colinton Road and Meggetland Terrace).