The photo in my previous post showed only the head of the nail. Unfortunately, this nail was a bit of an iceberg with about 2.5″ of it actually inside the tyre.

You can see that the nail has damaged the inside of the sidewall of the tyre, so sadly that’s an ex-BT021 as it is not repairable…

Here is the dead tyre with the nail head exposed.

I will be steering clear of those “unswept” areas of the road surface from now on…