Bitter Vetch, Lathyrus linifolius, judging by the leaves shown in the picture below and with thanks to Mark Goff.
The first of the flowering pea/vetch, the common name is confusing as it is not actually a vetch, according to Blamey, Fitter and Fitter in Wildflowers of Britain and Ireland.
Picture taken April 11.
When it was the home ground for Swansea City!
Boom boom!
I agree that appears to be lathyrus linifolius – bitter vetch. The lack of a leaf stem tendril is a good indicator. I grow bitter vetch on a semi-commercially for its appetite suppressing tubers so, short of digging it up to see if it has one, I would say it is Bv on the basis of the photo.
Thanks for the feedback, appreciated.