This is a genuine, good condition but incomplete British MkI helmet. Helmet is in untouched condition, exactly as it came to us as part of a large lot of 1917's, 1917A1's, and even some British MkI helmets.
The British MkI helmet started out as an evolution and the large scale mass produced development of the original War Office Pattern "Brodie" Helmet. The British MkI would go on to be used and manufactured by US Forces in WW1, as the M1917 helmet. It differed only slightly, namely the methods of attaching the chinstrap bales (British MkI's used split pins, American M1917's have rivets) and the seam of the rim attached to the edge of the helmet. British MkI's have rims that overlap, US M1917's have it flush. Additionally, US made M1917 helmets have a "Z" prefix on the steel lot code, British ones do not.
This helmet is marked BURYS on top of D04. Below that, there is an additional symbol i cannot quite make out. Burys is a rather uncommon maker in our experience.
Helmet is missing its liner. Chinstrap is present and is still soft. Chinstrap is marked with 7 1/8, this being the size when it still had a liner.
While we do not recommend wearing it, it would look great on display. Paint appears to be the original paint, though this one does have a ring of rust on it from long term storage.