Unidentified thistle

Unidentified thistle

Observation - Unidentified thistle. Description: This thistle is growing on a roadside verge, it is very tall (some are now 2m+) very slender, the flowers are quite a deep purple, and the leaves wrap tightly around the stem in a spiral. It is growing on a verge which is nutrient poor, and has Common Sp

This thistle is growing on a roadside verge, it is very tall (some are now 2m+) very slender, the flowers are quite a deep purple, and the leaves wrap tightly around the stem in a spiral.
It is growing on a verge which is nutrient poor, and has Common Spotted and Pyramidal Orchids abundantly.
I can't identify it though, any help greatly appreciated