The overturned lorry was indeed an open-topped bulk haulage job. It turns out to have been loaded with scrap metal.
The actual problem was that although it had come off the road and was on the verge, the particular point that it had come to rest was on the stump of one of the junction's light standards. The mangled remains being under the trailer, and those containing live power cables, was what caused the recovery people some concern.
