I'm fortunate in that I have a fairly new number these crooks, and they are crooks because these calls are illegal, have yet to catch up with, but I know for those who get them they can make life well-nigh intolerable.
Unfortunately, they're difficult to fight because they're difficult to identify until they're received. Spoofed CLI data isn't a clue, because there are legitimate reasons for spoofing CLI data, for instance making a call through a VOIP provider but wanting the recipient to get the number of your landline or mobile phone. CLI data not matching the source of the call doesn't mean it's SPAM. Nor will noting the numbers and blacklisting work, since the numbers sent bear no relation to the real senders, which again, so far as the PSTN is concerned, are probably those VOIP providers.
Reporting the calls to the ICO is not practical in many cases because the time taken to fill in the necessary forms is often ten or twenty times the duration of the call being reported, and unless you have pressed the call-back key and persuaded the criminal to identify the business commissioning the call (and most will simply ring off if they suspect you) the spoofed number means nothing to the ICO and they don't know who to contact. Besides, the ICO is very weak and will simply tell the perpetrators to stop at first. They will only prosecute if people continue to report the calls on a big enough scale, and most of us simply couldn't find the time for that. It would help if there were a key combination we could press that would automatically relay the call details to the ICO, but I don't imagine that's likely to happen unless a telco could actually advertise it as a selling point and gain enough profit to justify the investment in equipment. The current structure of most of the privatised industries, and I fear telephones are little different, is to leave the basic infrastructure in a single unit and allow competition between virtual 'providers' who, in reality, are just billing companies. They can compete on price and customer support, but not on quality of the basic service, since they don't actually control that. This structure makes price the main competitive factor and stifles innovation in the actual service being traded, because there is no incentive for that to evolve when the only competition is between resellers.
This is a problem which has to be solved, because it disrupts people's lives if they are interrupted while trying to relax or even sleep and cannot enjoy the quiet of their homes, but it will take innovation beyond the capacity of the current industry structures to provide that solution.
