PPS 10 Telecommunications·Page 29·A4
Preferred methods of distributing cabling
New cabling should generally be located underground or along external building surfaces, with consideration given to existing area distribution methods and operators' licence requirements for undergrounding apparatus and co-operation with other utilities.
In general, it is preferable to locate new cabling underground or along the external surfaces of buildings, but the method of distribution already prevailing in the area may be a relevant factor. Code system operators' licences contain specific provisions about the undergrounding of apparatus (with the exception of service lines), and about the need to service new development in close co-operation with the developer and the other utilities so that underground ducting for a number of undertakings can be provided during development or any existing suitable ducting used.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/PPS 10 - Telecommunications.pdf