Glider90 & PN, possibly relevant to your posts - I don't know when it started,but certainly in 1982 onwards Airway Blue 1 (latterly Bravo 1 as previously discussed ), was not available to GAT from 5NM East of OTR to 5 West of DOGGER (later,DOGGA ) at FL140-FL160,as these levels were reserved for crossing military aircraft not under radar control .