The last example of the Newcastle/Gateshead inter-urban services. The 66/67 ran between Benton Estate into Newcastle, across to Gateshead, then operated the Dunston Loop. The Dunston Loop or Circular has had a few different numbered services operating it. After the 66/67, it was the 58/59, then the 67/68, and finally the 64/65 (with an added 164/165 variation of it) before being absorbed into services that operated in the West of Gateshead. I believe that nowadays it has been amalgamated into the 49/49A/49B/49C set of services as well as the 95/95A.