Can I block certain telephone numbers?

[#1]

Hi
Just wanted to know if there was anyway of blocking unwanted phone calls? I've got the Home Phone and Broadband package from Force9, my telephone number is ex-directory and I registered my number a while back with the telephone preferences service.
The problem is that I'm getting calls from MORI (The research and poll company). I've been to their website and it appears that there is nothing I can do about it http://www.ipsos-mori.com/phonecall/ (makes for very interesting reading). Apparently I'm unfortunate to have had my number randomly generated, this is all well and fine but we are now getting at least 1 call a week from them; this may not sound like a great deal, but I've gone to the trouble of excluding my number from anyone other than those I wish to have my telephone number, I think that the statement on MORI's website is a bit lame to say the least, and in effect seems to but the ball back in my court!
Any help greatly appreciated

[#2]

Suggestion: When they call, excuse yourself briefly (take a pan off the stove etc.) - put the phone down and leave them hanging on till they give up - saves them bothering some other unfortunate person!

[#3]

If they're witholding their phone number you could have Anonymous Call Reject added to your calling features but it costs £1.50 per month. If they aren't, I don't think there's anything you can do about it.
I'm not sure if BT still do "Choose To Refuse" but I don't think PlusNet offer that service anyway. Might be worth asking about it.
Regards .....

[#4]

I do something similar.
I  ask who's calling. Once the've told me  who they are , if they are telephone sales  etc, I reply, "I will go and fetch him"
About 5 minutes later I will go back, pick up the phone to find  surprise , surprise, they have hung up. Do this a few times and they will soon stop calling.

[#5]

Thanks for the advice guys, to be honest I didn't think there was anything I could realy do! I think I might go for the hang up as soon as they announce them selves, once again thanks for taking the time to read my post.

[#6]

You could do this: Pull a stunt on a telemarketer, watch out it will have you in stitches.   

[#7]

That's brilliant Gary - I'd love to do that to a marketing person - especially the one that keeps offering me a free mobile phone and then sounds astonished when I say I don't want one!!!!
Tracey

[#8]

I once came across a guy's site where he has a load of different sound clips of sales calls where he turned the tables on the sales person. Usually they couldn't wait to get him off the line. Wish I could find it again.
......looking.