Confidence: I'm as sure as I can be.
Notes: The locally common comfrey hybrid, in this case showing the blue of its asperum parent. Caucasian Comfrey has pure blue flowers, a much less deeply divided calyx and relatively broader leaves. A nice plant but this is not it. Caucasian Comfrey is shown really well in the poster's past observation at http://www.ispot.org.uk/node/112544