Euura bridgmanii is a sawfly that causes a gall to form on Sallows - broad-leaved species in the willow family, including Goat, Grey and Eared Willows  (Salix caprea, Salix cinerea and Salix aurita).   The galls protrude from both sides of the leaf, and are often reddish or purplish; they usually do not touch the midrib. 

Similar bean galls are formed on narrow-leaved willows and on Purple willow.  Euura (Eupontania) pedunculi also form galls on sallows, but the gall is underneath the leaf and there is only a slight mark on the leaf surface.   The gall midge Iteomyia major forms large galls on sallow leaves, but these are associated with the midrib and usually in a group of several coalesced galls. 

Gall  Adult

You must tell us the type of Willow that the gall was on and attach an image of both the gall and the whole leaf.

Hedgerows and damp places where the host willow trees are present.

Common in Britain.

Common in Leicestershire and Rutland.

https://www.sawflies.org.uk/euura-bridgmanii/