My ID book states that small hop-clover "is similar to black medic but has straight, not coiled, pods". Could anyone help me out with this one? I don't really follow where the pods are...
Hop Clover is Trifolium campestre, which looks quite like this except that the fruiting head has balloon-like petals curling over the tiny pods, and I can't see any like that in your pics. It could be Yellow Suckling Clover, T. dubium.
I'd agree with Trifolium dubium. The pods are in clusters, the pale brown items in the photos - each flower (of which about 20-30 per flowerhead) develops into a single small pod. In Medicago lupulina (Black Medick) the pods are curled, and (as per the English name) black.