[emilyfm]

It was the only number that could not be dialled by accident by letting go of the dial too early. The aim wasn't to dial quickly, it was to avoid accidental calls.

Rotary dials in New Zealand were the other way around (sending ten minus the number dialled pulses) so the emergency number there was (and still is) 111 for the same reason: the hardest to dial by accident.

[jayd16]

Rotary phones swirl the opposite direction in the southern hemisphere?

[stuaxo]

Apparently birds sitting on phone lines could trigger 111.

[grkvlt]

Yes, in e.g. the UK, perhaps, where 1 was two pulses (although they would be more likely to dial 000, I would think) but not in NZ, for the reason given in the comment you replied to.

[peteri]

Pretty sure 1 is just one pulse in the UK. Zero is at the far end of the dial next to 9.

[grkvlt]

You're right, it's been a long time since I used a rotary-dial phone (or even a keypad phone that used pulse dialing...) and information like this gets dropped off the stack of 'useful things to know' eventually ;(

[boznz]

Never even thought to ask the question and I live here, you learn something new every day..