There seem to be a lot of these shed skins this year - far more than I usually see
there is no split, it looks like the whole thing, perhaps it has a fungus disease, like the entomophthorales that attacks flies?
There are loads of them like it this year.
Identifying a fungus or other pathogens that might be responsible is beyond me I suspect we will never know.
a possibility perhaps, I recommend posting the image again as a new observation in the Fungus group.
using the association feature. So far that has not attracted any agreements that it is fungal.
Lat/Lng: 51.540316447216, -0.32921433448792
OS grid ref: TQ159837