Length 4.5 to 6 mm.  A very variable brown species with paler wing veins; often with dark mottling in wing cells. Dissection of male to examine internal genitalia - the aedeagus - is needed to confirm identification. 

other Streptanus, and other Deltocephaline leafhoppers

males

Provide photos from top and side view, but identification should be confirmed by examination of internal genital structure of males. 

Grassland

Summer-Autumn.

Common. (ref.: UK Auchenorrhyncha checklist 2021 on British Bugs website)

Occasional; possibly under-recorded due to identification difficulty

https://www.britishbugs.org.uk/homoptera/Cicadellidae/Streptanus_sordidus.html