[Station X]

The CLI could have been spoofed as is the case with most scam calls. Or it could have been a 112 call generated as a result of a line fault. The proverbial "JCB through a cable" could generate hundreds of these calls. The cure IIRC was to run a timer after the digit 2 was received and if further digits arrived before the timer expired the call was assumed to be false and released. 112 would be fine in an all tone dialling environment, but I believe it was a condition of BT's licence that they continued to support loop disconnect dialling, something vintage telephone users are grateful for!

Emergency calls used to be "manually held" which meant that the call could not be cleared until it was released by the operator, so police arriving at the premises could speak over the connection and confirm where the call came from.

There was no CLI in those days so the operator would ask the caller for their number. A second operator would then dial that number and confirm the line was busy. They'd then used the "Trunk Offer" or TKO facility to listen in on the call.

TKO's original use was to enable the operator to offer a trunk call to a busy line.