Shiny, black. Short elytra. In leaf-litter. Several focus-stacked images combined.
No interactions present.
Meant to add that the reason it is Stenus is down to the bulging eyes and the parallel-sided body shape, very characteristic for the genus as a whole. Most Stenus are blackish although a few have lighter spots.
Entomologist and biological recorder
Lat/Lng: 52.198229, -1.546443
OS grid ref: SP310556