A plant growing in a very damp drain. I have have posted an image containing two separate photos, one of the leaves and one of the flower heads.
Water Cress - either Nasturtium officinale or N. microphyllum - from this image I cannot say which (as you need to see the mature siliques and seeds to make an accurate identification)
Thank you Peter I will revisit later and source some seed pods
(JPG format, max 500kB)
A plant growing in a very damp drain. I have have posted an image containing two separate photos, one of the leaves and one of the flower heads.