History
Sibleys, named after nearby Sibleys Manor, was in service by 1959 as an intermediate point on the London to Norwich link for Anglia Television. At this stage two dishes were installed on a relatively slim self-supporting tower. The building was a timber-framed type - the "standard" design was not yet in use.
The site was later incorporated into a planned route from London to Leeds, requiring a new structure to allow future growth. Other sites on this new route were provided with a "standard tower" but Sibleys received the prototype of a new modular design known as the "Daffodil" tower. Work on the foundations started in 1965 and the structure was reported as complete by early 1967. The GPO Engineering Department Annual Report to 31 March 1967 notes: "The tower carries paraboloid aerials instead of the horn aerials for which it was designed. This is due to an advance in paraboloid aerial design"
The section from London to Sibleys (via Kelvedon Hatch) was shared between the Leeds and Norwich routes, ultimately limiting the capacity of both. A new site at Hertford Heath was planned in the mid-1980s, allowing the routes to be fully independent, however it is unclear whether the additional capacity was used. A planning application in July 1985 "Extension and alterations" may be connected to this development - details are not currently available but photographs confirm a modification to the top level of the tower at some stage after 1976.
