Interesting note

"One important advantage enjoyed by the transport industry in the British Isles was the absence of internal customs barriers or tolls (apart from turnpikes). In most of Europe they were ubiquitous. Especially in rural areas where cash was hard to come by, transient merchants were tempting targets. When they crossed a frontier, entered a town, forded a river, passed over a bridge, ascended a mountain pass, or whatever, there was often someone exacting a fee.", [Tim Blanning, The Pursuit of Glory]