TPS is a confidence trick
TPS does nothing. They have the power to impose fines that are intended to ensure compliance (up to £5k per call to a TPS registered number and I think imprisonment is an option not only for the MD of company making the call but also for the individual employee).
An FOI enquiry found they have NEVER imposed a fine of any size or any other penalty.
If they get enough complaints about a particular company they write a polite letter asking them to take more care about who they call.
I think TPS complaint monitoring is subcontracted by the ICO to an organisation funded by the marketing industry.
It's not even that easy to file a proper complaint as the calls are usually "number withheld" (or more recently to get past those who have such calls blocked by their telecoms supplier for example, some seem able to use a faked caller ID). Ask the caller for their name, company name, address, phone number - at best you get: "Can't give you my name because of the data protection act" but commonly they know the reason people need that is to log a TPS complaint so they end the call.
TPS is basically a confidence trick, the authorities being seen to do something but prefer to look after the interests of the marketing industry than the electorate - after all we only get one vote every 5 years, the marketers get to entertain MPs and make donations to political parties every day of the week.
On a similar note, junk emails, a marketer involved told me he'd once accidentally sent a mailshot to his list of people who had explicitly requested no further mailings from him - it generated no complaints and more business than any of his mailings to opted-in addresses. That's why marketers regard TPS registratrants as "good prospects", we get fewer calls so are more likely to respond and the only downside risk is an ineffective TPS complaint.
I don't bother completing TPS reports any more, it just means each junk call takes me time and effort.
Read the TPS web site - worded to emphasise the downside (!) of blocking unsolicited calls (that you might really want some of those calls!).
The con-artists have also got in on the act, there are companies who charge £££ to block your sales calls. All they appear to do (apart from taking your money of course) is register you with TPS.
Also there are all sorts of clever devices to help you block these calls - but why the heck should I pay £££ to prevent someone invading my privacy? I got a phone for my convenience not theirs.