Slightly obscure, but still tech-related - having to give them your number when you call 999

Sandtree

At a guess, because not all CLI are true and/or can be called back on.

For example I had a call from HMPO today and the CLI comes up with 01753 number which if you call back it states that they are a outsourcing call centre working for blue chip companies and if its important they'll be calling back then it hangs up. Clearly if that agent had called 999 they'd want to give a different telephone number that does accept inbound calls.

Similarly we use VOIP at home and can set the CLI to one of a number of different numbers which includes my mobile... without clarification they'd presumably see the CLI as a mobile and potentially try to locate my phone rather than thinking its a call being made from our home.

Rusty190

I'm making an assumption here that the emergency services system works in a similar way to other health care phone systems.
If so, they will see your number on their phone system when you call but they then need to input the number on the computer record they are creating as they answer your call.
It's the first thing they ask for as, should you be cut off for any reason, the risk is that your number will be lost to them too so they can't call you back.
They need to note contact details first as once folk launch into the reason for the call, it can be difficult to get them to pause for breath long enough to get contact and location  details.
Also, if you get cut off midway through explaining the reason for the call, they can still send help to you.
They can't do that if they can't contact you/don't know where you are.

Marcon

Rusty190 said:

It's the first thing they ask for as, should you be cut off for any reason, the risk is that your number will be lost to them too so they can't call you back.

Correct. The Red Cross site confirms they ask for your number so they can all you back if the call is disconnected: https://www.redcross.org.uk/stories/health-and-social-care/first-aid/how-to-call-an-ambulance