Quote Originally Posted by steve456 View Post
All these bizarre links saying that you can't dial 999 without network coverage are, as far as I am aware, incorrect or massively out of date.
this is a vaguely interesting point so I found this on tinterweb:

This isn't quite correct.

Whilst the GSM spec allows for network locked phones to roam onto other networks for emergency calls, the UK networks do not allow it - they have no GSM roaming agreements between UK networks - so if you're out of coverage from your provider, you cannot roam onto another UK network to make calls, emergency or otherwise.

Again, whilst the GSM spec allows handsets to make emergency calls without a SIM, UK networks do not allow it.

The simple story is that to make an emergency call in the UK you require:

a.) An enabled and active SIM from network 'X'
b.) A handset which can normally make calls on network 'X' (ie. isn't locked out from that network)
c.) Network coverage from network 'X' at current location.

If any of those requirements aren't met, then you cannot make an emergency call (or a normal call either). Again, the GSM spec does allow this to happen without any or all of these, but the network can decide whether they want to allow it, and in the UK, they haven't.

The handset may think it can make emergency calls (ie. "Emergency calls only" but when the user would try to make that call, they wouldn't be successful (in the UK).

So, if you set fire to yourself, don't think you can call a Lifeboat out to Mermaid's Pool