Have just had a call which displayed the incoming number as 001000723; intrigued I picked up but didn't speak, it's a silent call which then goes dead.  Googling brings up a number of posts on other sites saying it's a scam number from abroad trying to sell a device to stop unwanted calls.  Just wanted to alert others, don't bother to answer it.  Interestingly, it follows a recent plague of "private caller" incoming calls.  We are on TPS.

I have for long been trying to remind people that CLI is an "information" service - it can never be a way of assuredly advising of who is calling. It never gives names, it can only give numbers, so unless the number is recognised it does not tell you who is calling.

There is an absolute right to withhold CLI when it would be presented as the number of the line from which one is calling.

The number of the line from which a call from an outbound call centre is made is of little use anyway. It would never be published or dialled, as it cannot incoming calls. A call centre will therefore present no number at all or a "presentation number". My belief is that a "presentation number" should only be offered to enable continuation or follow up of a call - as telephone numbers are only for the purpose of making a telephone connection. Sadly they are often used to solicit wasted return calls that do nothing more than advise the type of call that was made - which the recipient would know anyway!

It is the duty of every caller to identify themselves to the person who answers their call. If CLI is offered and the number is seen and recognised by the person called, then this can be helpful to them.

Anyone is free to acquire a service that filters calls based on CLI, or assists them in choosing whether or not to answer a call in person. All such approaches however carry a risk of missing important or wanted calls. Most of role played by CLI in the issue of dealing with nuisance calls is mistaken or misrepresented. Its significance is commonly overplayed.

For the case in point, failing to speak when picking up a call is likely to cause a silent call. Many call centres use "Answering Machine Detection" equipment which samples the sound heard when the call is answered in the (commonly mistaken) belief that this will enable a distinction to be made between a live voice and a recorded voice. Only if a "live" voice is heard will the automated dialler transfer the call to an agent.

It's a difficult situation to judge when picking up the phone with a strange number or "number withheld" displayed on the handset.... however I always just say Hello....

I recently got a landline installed to which few people have the number and I received a call on it, when I was not expecting to (most people ring my mobile or text me)... when I picked up the call and said Hello, it was clearly a call centre and the caller was trying to either sell me something or was conducting a survey... I simply said no thanks and they ended the call...

As it's been said many times before, the industry needs to be vastly improved and companies need to be dealt with if they call people for no legitimate reason...

I appreciate this is somewhat of an unusual reply.. but that's my feelings..  :)

If they ring again, it maybe worth speaking.. even just a hello, to see if you get a reply...

I have had occasional calls with odd numbers. I think I had one that was "1111111111". As others have said, CLI is readily falsified so it's no problem for a scammer to put anything they like as CLI.

It's also possible for a companay's wrongly configured telephony system to present nonsense CLIs. I've not yet experienced this.

One of my favourite appoaches to unwanted calls is this. When they ask for me by name, I ask in my smoothest professional voice to hold on while I find him. If I'm feeling generous I leave the handset by the radio so they get music on hold.

I rather like a comment I heard that someone keeps a whistle beside the phone and when answered and found a Scam Call starts the caller talking and then a short reply and a blast on the whistle.

Depending on my mood I sometimes like to string them along, when told to turn PC because it has reported a fault I show surprise and explain 'That my PC clever because it is in a removal van halfway up the M1.

Or if not in a happy mood give them a quick tutorial of East-end culture language   XXXXXXX!!""&***  ;D