This one might have me fooled. Its a Capsid or Mirid Bug - one can tell by its distinctively coloured cuneus (triangular bit behind the head - see my first capsid/mirid bug post).
This one, like the red one in the first post, was a nippy little bugger too. It just didn't want its photo taken, unlike pretty well every other insect I've snapped. It runs fast does the Capsid bug.
Today's Mirid Bug was almost black though, and seemed to have bulging eyes and a wide head - these are features normally associated with what I like to call the "Gothic Mirid Bug" (Capsodes gothicus).
However, that bug is hairy, and mine was either bereft of hair, or, erm, clean-shaven!
So, I suspect, this morning's Capsid or Mirid Bug is simply a darker version of the first one I took a photo of (just), some posts back. This Mirid Bug does range in colour from brick red to almost black.
Almost certainly NOT the "Gothic Mirid Bug", but Deraeocoris ruber instead.
Whichever species it is (and I'll post a photo on the WAB site to tempt the competitive streak of the entomologists there to be the first to positively identify it), its good that its in the garden - it eats aphids.