if you are talking about marketing calls, register with the TPS, it's a free service and extremely good. I don't get any nuisance calls any more
http://www.tpsonline.org.uk/tps/index.html
Tell them to hold on, you can see the person they need to speak to in the garden. Put the phone down preferably with Jeremy Kyle at full volume, but dont hang up. They will eventually get the message. They are paying for the call.. Not You. I love doing that.
Same here, they always begin 0161 so I know to ignore them.
0161 6674350
0161 6674351
0161 8149323
0161 9023780
0161 9023789
0161 4293359
These are the ones I have blocked on my mobile so far, they drive me crazy, especially as they tend to always manage to phone when I'm in the middle of something.
I get very few because I am registered with TPS and am ex-directory. If caller display shows "international" I always answer and say it is the fraud squad. They have put the phone down before I finish. Apart from that if I do not recognise the number I do not answer.