The section Operating Your Ham Radio in an Emergency from Ham Radio For Dummies recommends using an "emergency autopatch" to reach the emergency services when reporting an emergency from an amateur radio transmitter:
- State clearly that you are making an emergency autopatch (a feature that allows you to make a telephone call from your repeater) and then activate the autopatch system.
If you cannot activate the repeater's autopatch, you may ask another repeater user to activate it for you. Or, on HF or VHF, you can ask for someone to make an emergency relay to 911. In this case, report all the necessary material and then stand by on frequency until the relaying station reports to you that the information is relayed and the call is complete.
Dial 911 and when the operator responds, state your name and that you are reporting an emergency via amateur radio.
Follow the directions of the operator from there.
If the operator asks you to stay on the line, do so and ask the other repeater users to please stand by.
- When the operator finishes, release the autopatch and announce that you released the autopatch.
Apparently autopatches (aka "phone patches"?) are common in the USA, but searching the Web has turned up scant information about them in, for example, the UK.
That makes me wonder: are they legal in the UK, and if so, where can I find out more about how they are regulated and used there?
Likewise for other jurisdictions.