Barkfly (Valenzuela flavidus)
You could be forgiven for never having noticed any of the 90 or so members of this family of insects given their tiny size.
What alerted me to this specimen was its constant movement and fussing over what turned out to be a clutch of eggs.
More details on this species here:

''Valenzuela flavidus'' is a species of Psocoptera from Caeciliusidae family that can be found in United Kingdom, and sometimes Ireland. They are also common in Austria, Azores, Belgium, Bulgaria, Canary Islands, Croatia, Denmark, Finland, France, Germany, Greece, Hungary, Italy, Latvia, Luxembourg, Norway, Poland, Portugal, Romania, Spain, Sweden, Switzerland, and the Netherlands. It is also widespread in Near East. The species are yellowish-black coloured.