A dark, almost black bug, with brownish hind tibiae and black antennae and foreparts.   Males are macropterous; females are usually brachyperous and have a squat rounded shape. 

Orthocephalus coriaceus has black hind tibiae, and the males have yellowish streaks on the corium.  Females are very similar.

Good photographs showing colour of hind tibiae are needed

grasslands

Widespread, but local  (ref: British Heteroptera checklist 2021 on British Bugs website)

Rarely recorded

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