The AMES Type 85, also known by its rainbow code Blue Yeoman, was an extremely powerful early warning (EW) and fighter direction (GCI) radar used by the Royal Air Force (RAF) as part of the Linesman/Mediator radar network. First proposed in early 1958, it was eleven years before they became operational in late 1968, by which time they were already considered obsolete. The Type 85 remained the RAF's primary air defense radar until it was replaced by Marconi Martello sets in the late-1980s as part of the new IUKADGE network.

Linesman/Mediator was a dual-purpose civil and military radar network in the United Kingdom between the 1960s and 1984. The military side (Linesman) was replaced by the Improved United Kingdom Air Defence Ground Environment (IUKADGE), while the civilian side (Mediator) became the modern public-private National Air Traffic Services (NATS).