A very small predatory bug, c.2mm. The darkest forms are almost completely black, including wing membranes.  However, paler examples can be found, and these are hard to identify.  Antennae and front tibiae are paler. There is a single hair on the anterior and posterior angles of the pronotum. 

Other Orius and small Anthocoridae. 

Good quality photos. Paler specimens may need to be dissected to confirm identification.

Common (ref: British Heteroptera checklist (2021) https://www.britishbugs.org.uk/systematic_het.html

Not known. Few records exist, but probably under-recorded due to difficulty of ID

https://www.britishbugs.org.uk/heteroptera/Anthocoridae/Orius_niger.html