Confidence: I'm as sure as I can be.
Notes: Oh dear, the usual error! This is NOT, repeat NOT Symphytum x uplandicum, though often mis-recorded as such. It has rich purple flowers with no trace of blue, leaves gradually narrowed to the base and continuing down the stem as conspicuous wings to the next internode. By contrast, S. x uplandicum has slightly less tubular corollas, with distinct blue tints, leaves more abruptly narrowed at the base, the petioles continuing as narrower wings that generally do not reach the next internode. It is more common than S. x uplandicum in the north and many, many records of S. x uplandicum are incorrect. This purple-flowered version of S. officinale has long been called 'var. purpureum', but it is now considered the 'type' variety of S. officinale and we should call the white-flowered plant 'var. ochroleucum' (unless it is the smaller, more creamy-flowered subsp. bohemicum of the East Anglan fens). See further comment below.