Britain's busiest coastal shipping flows

Which British coastal convoy route carried the most traffic?

Traffic was heavy around the whole coast, with especially intense flows on the east and south coasts and from the west coast toward London.

The answer highlights the east coast, south coast, and the west-to-London movement while resisting an overly neat ranking. Cargo origins, destination ports, and linked convoy legs kept several corridors busy at once. Thinking of the system as a roundabout better captures its continuous circulation.