Have you had this email forwarded on to you yet? The one that claims you can dial 112 on the tube and it will put you through to the emergency services.
Well, unfortunately it's complete rubbish.
The email has spread so far and wide that Transport for London have had to issue a press release about it, saying:
A misleading spam e-mail has been widely circulated which claims that by dialling 112 you can get through to 999 even without having an available signal on your mobile phone - this is completely untrue...The 112 number does link people through to 999, but it only works if you have a signal on your mobile phone. If you have no signal bars on your phone, it will not work.
It will not divert to a satellite signal.
So there you go. That's our good deed for the day.