Back in the day, with a operator, mostly municipal who only operated within the Town/City boundary, but you had places just the other side of the boundary that was served by another operator, like in Preston, Preston Bus operated in the Town/City boundary, but there is a couple of places just outside Preston like Penwortham & Longton but were served by Ribble buses, as they are in a different council area, South Ribble.
Likewise in Tyne & Wear, the PTE mostly operated services in the Newcastle, South Shields & Sunderland council areas (although the TWPTE had a couple of routes to Ponteland which is just over the county boundary in Northumberland), it was United & Northern that operated most of the other services.