The UK Moth website explains the name of this rather bland-looking moth: ‘The “Pistol Case-bearers” are so named from the resemblance of their larval cases to an old flintlock pistol in shape.’ And I think you can see that likeness in my photos.
I’d not seen anything like these before so turned to some Twitter experts for help with their identification. Fortunately, Rob Edmunds, of British Leafminers website fame, was able to confirm that these are indeed the larval cases of the Pistol case-bearer moth (Coleophora anatipennella). Their feeding makes tiny holes in the leaves, which you can see in the photos above and below, and these particular ‘pistols’ contain larvae that have over-wintered in their cases, which Rob thinks are now ‘in position pupating on the upper leaf surface’. Nature never ceases to amaze me!