Pilophorus clavatus

Length 4.5 mm. Pilophorus species are rather ant-like bugs, which feed on aphids and have silvery bands on the forewings formed by pale hairs. In P. clavatus the posterior band is not continuous across the forewings and is displaced forwards in the centre (where it crosses the clavus). The pronotum and forewings are also covered in fine hairs.

Photographs showing key features required. 

On Willows. 

Summer-Autumn.

Locally frequent across much of Britain.

Seems to be uncommon in Leicestershire and Rutland.

https://www.britishbugs.org.uk/heteroptera/Miridae/pilophorus_clavatus.html