Originally Posted by
PhilipK
[COLOR=#000080]That may deter the legitimate marketing companies who are based in the UK from calling, but there are many ways around this.
The vast majority of spam calls originate from oversea, and are using VoIP, so they can set the Caller ID Presentation (the number that comes up on your handset) to be whatever they like. I've received calls purportedly from numbers that are just one digit different to my own mobile's number - their hope is that you glance at the number, think "oh, that looks familiar" and so answer it. They will also use a local dialling code when calling landlines (again, because people are more likely to answer a call that looks local).
The UK-based companies will claim that they are doing a "survey" or something similar, so that it's not a "marketing" call.