Just had another one of them scam calls - an Indian lady trying to convince me that I needed something for my new computer. (New??!). She hung up after several requests to find out where she got my number.
1471 revealed, in an American accent, "There is a semantic error in the system" or near enough. Presumably one of those offshore jobbies where they insert a spoof number, which in this case caused the system to fall over.
I did a goggle, and found a link to, oddly enough, a forum on my ISP, talktalk. It advised, for malicious calls like that, to 1477 it instead of 1471-ing it to log the call with its real details. I did so, and was informed "The last call has been logged as a malicious call".
Hopefully there is a system growing that can combat the increasing army of scammers and plain, simple nuisances, like BskyB. Dont know if it is available on other systems, but it might be.