Last mile.......
You'd be suprised how inbred the telco industry is, I work for a very large globa telco and we often get third party tails from cable and wireless, you'd be suprised (or not) how often they are provided by BT (OR COLT etc)
Also, Our own internal sales teams don't seem to understand when a customer says they want geographic diversity there is no point having 2 seperate circuits going between four different sites if your on net portion is on the same fibres! I have had to point out that they really should get a 3rd party supplier in some of the corners of our more far flung empire (Ex USSR springs to mind) but they still dont get it!!