Pseudoturritis turrita Tower Cress
This plant has small pale yellow or whitish flowers like many other crucifers but the very long, pendulous, twisted fruits are so distinctive, it is easy to recognise from quite a distance. It is occasionally found introduced in the British Isles but usually only dotted around in southern England.
The name has recently changed (New Flora of the British Isles Third Edition by Clive Stace 2010) from Arabis turrita to Pseudoturritis turrita.