Approx. 40cm in height. Tube-shaped flowers hanging from stalk.
No interactions present.
I think this is Melilot (Melilotus officinalis)
How can you tell if this is ribbed Melilot or Tall Melilot without examining the flowers?
At highest resolution of the image (especially on a large, HD monitor!), the proportions of the parts of the flower can be made out with reasonable ease. Also, as a confirmatory character, the ribbed fruits are starting to form.
As regards my own agreement, I did however, recognise it from the thumbnail. In the field I seem to know the two species apart before I examine the flowers. What I DON'T know is HOW! I guess that some subtlety of colour or colour combination triggers the name.
Anyhow, I belive the present ID to be sound.
Thanks for all the comments.
Lat/Lng: 51.81094, -1.18707
OS grid ref: SP561127
Amongst hedgerows of tall grass along ditches of wetland reedbed reserve.