No obvious leakage has been found by workmen digging into the hole as far as the pipes.  Apparently the ground is quite sandy once the road surface is broken into.

There is no obvious reason for this hole to have appeared, so the issue is considered to be resolved. The sub-soil has been replaced and the road has been reconstructed with two layers of tarmac.

Today they will top surface it, and then a curing period will be needed before anyone can drive over it.

The network supervisor is hoping that the road may be re-opened this afternoon and certainly by the peak period for traffic.