Identifying illegal callers using withheld numbers

[#1]

As per title, is there any way of tracing illegal calls if the caller's number is withheld? Would this be Plusnet's or BT's department?
Recently have been getting repeated calls selling solar panels, double glazing and kitchen scrappage schemes. The calls consist of a robot message played down the phone, which I believe is explicitly illegal anyway. 
It is also difficult to hang these calls up, you find the illegal caller is still on the line even if you hang up, wait a while and then try to use the phone. If you then press any keypad button, this triggers a message saying you have opted-in for further nuisance calls, when in fact you were trying to dial out.
ICO have been informed. Would be helpful if I could get a handle on who's doing this, though.

[#2]

Hi
It may be worth having a look and maybe registering for TPS (Telephone Preference Service). You can do so here: http://www.tpsonline.org.uk/tps/index.html
We can also provide Anonymous Call Reject at an additional cost of £4 per month. This service rejects any call where the number is withheld. You can view a full list of our call features here: http://www.plus.net/support/phone/call_features.shtml
Hope this helps!

[#3]

Your other option is to humour them enough until you get their company details then make a formal complaint about them.

[#4]

If there's a live person on the line I usually use one of these. http://www.amazon.co.uk/Hawkins-Bazaar-Sound-Machine/dp/B002VEOE8C/ref=sr_1_5?ie=UTF8&qid=1392652242...
I've found TPS to be a waste of time in spite of my number being registered with them. The companies get round the TPS by describing their calls as "marketing/surveys".
Bit childish possibly but there is a degree of satisfaction after use. They usually don't call again after being zapped with a fart.

[#5]

I got fed up of international calls, bought one of these which has stopped them completely.
http://www.amazon.co.uk/CPR-Global-CPR106-All-in-One-Blocker/dp/B004BTVQ5E/ref=sr_1_1?ie=UTF8&qid=13...

[#6]

Quote from: Hobo

I got fed up of international calls, bought one of these which has stopped them completely. http://www.amazon.co.uk/CPR-Global-CPR106-All-in-One-Blocker/dp/B004BTVQ5E/ref=sr_1_1?ie=UTF8&qid=13...

That might be an idea. I don't fancy blocking all unidentified callers because that could be a major faux-pas if someone wants to do £1,000,000,000 of business and gets cut off. Not that this is likely, but.. well, you know what I mean. Something which required an unidentified caller to press a key sequence like *#  would be effective against robots, anyway. I wonder if that is available. Basically, captcha for phones.

[#7]

How does this work with international callers???  The reason I ask is that when they call us it just shows up as INTERNATIONAL on the caller display.  With no number available then the machine surely can't block them.

[#8]

CLI information is a data stream, so both text and numerals can be matched. For international calls, it is currently a blanket block using the word; what will happen when international calls provide additional info, I don't know

[#9]

I'm registered with the TPS and I still get far to many off these calls.
Every time I can ID the caller I report them, but recently I have been getting 4 or 5 calls a day from a number on my phone showing as simply 00.

[#10]

In my experience signing up with the TPS doesn't stop unsolicited calls [tho' there is no way of knowing how many it reduces them by] however it does make companies hang up pretty quick once you request information of who they are and say that you are going to report them to TPS.

[#11]

My experience is that TPS took a good while to kick in but now I don't get any unwanted calls at all. However, I do have choose-to-refuse on my line so I can't say how much that impacts the volume of calls.

[#12]

I'm considering building a device which lets through calls from numbers on a whitelist but plays a message if the caller is on an online blacklist or withheld/international which says "As you are on a blacklist, have withheld your number or are an international caller, please press 3 to be connected, if you are making an unsolicited call, you will be wasting your time and told exactly where you can shove your call" 

[#13]

I've been on the TPS list for YEARS. Totally USELESS 
I was getting blanketed with these spam calls a couple of years ago (just after moving from BT to PN!) and I got one of the CPR blockers, been in use for ~18 months and if I get a spam call now I just press the button and the number gets blocked there after. I block INTERNATIONAL & withheld callers. If they want to speak to me they can use a REAL number  Did wonders for my blood pressure as well 

[#14]

Quote from: Anteaus

Something which required an unidentified caller to press a key sequence like *#  would be effective against robots, anyway. I wonder if that is available. Basically, captcha for phones.

Optionally TrueCall.Call Blocker can require an unknown caller to press a specified number key before it will connect a call.
http://www.truecall.co.uk/home.aspx

[#15]

Quote from: Hairy

I've been on the TPS list for YEARS. Totally USELESS

Wholeheartedly agree,  they can only be effective against UK based companies.

Quote

If they want to speak to me they can use a REAL number

There are a number of valid reasons why 'withheld' is used:

• Where a potentially sensitive call is targeted at one person in a household, It may be unhelpful if the source of the call is identifiable by others in the household.  e.g.  Citizens Advice Bureau;  Social Services;  Doctor etc..
 

• Where an individual is 'working from home'  and does not want their home number to be mistaken for the corporate number

Sadly the significant misuse of the functionality by scammers / spammers has reduced the legitimate use.
Maurice