Nuisance and Spam telephone calls are a problem for all, and a significant percentage of these calls come from "spoofed" UK telephone numbers that cannot exist (Unused STD Codes, and number blocks allocated for Fictitious purposes).

It would be relatively trivial for the Telephony provides (both Public Telephone Operators - PTOs - and Mobile Network Operators - MNOs) to detect and drop such spoofed calls, but they show no interest in doing so.

OFCOM, as the regulator, should therefore request, and, if that fails, compel them to do so.