Attactagenus plumbeus

The only British species in the genus.

This keyed to Attactagenus smoothly but given that it's a fairly scarce species I did double-check. Marram Weevil Philopedon plagiatum (which I don't suppose would be much more likely at this location) differs in having a more obviously expanded apex to the fore tibia. Other similar species differ in other ways, such as having a broader base to the elytra.

Attactagenus plumbeus showing fore tibia, Wendling Beck Environment Project (Norfolk, UK), 30th April 2023