well spotted Swifty a fair assumption to the well trained eye, I would confirm it resembles the remains of a well tugged number ...
On a more serious, I hope the Brother Scaff recovers soon and no harm meant by the Criac above, I recall a similar incident when a cable was passed through the inside of a tube, the tube was cut with the resulting consequences...my pet hate is welders pushing their spent rods inside tube, its a ca nt when you come to strike...
Remember hearing about a guy working for beacon scaffolding in London!
Went to strike a council job in Camden and was killed outright cos some **** had wired the mains to the scaffold! Very sad!