I read that because back then phones used pulse dialling, it was possible for accidental calls to be made by telegraph lines swinging in the wind and tapping trees etc,While we are talking numbers, does everybody know why we have 999 as the emergency number and not something like 111 that would have been quicker to dial? Well I'll try and explain my understanding.
In the early days, telephones were analogue. Numbers were dialled, or could be tapped on the handset rest. You might think that a lower number (111), would be quicker than dialling or tapping 999, but they found that there were too many miss dials by people dialling higher numbers. It was easy to hesitate when trying to dial a high number and thus allow a 1 to be registered and thus a false call to the emergency services.
So the experts decided that it had to be three nines, as there could be no mistake that the emergency service was required and only genuine emergency calls got through.
Now that phones are digital, it would not matter what number was used as the chance of an unintended number is no longer possible.
Well that's my story. I think it's true as it was told to me on a BT course.
But if you know something different.....