[Kushan]

That's precisely it, the cost. I believe that OFCOM come down hard if telephony services aren't kept up and fixed promptly. Particularly as there's a human life factor, quite a lot of people (elderly and disabled) rely on the phone line for lifeline serivces so a downed line could literally be the death of someone. That's one of the reasons why everything has battery backups.

The problem with a VoIP service is the battery backup would have to extend into the customer's property and keep their hub alive as well. I don't know if there's technology to do that.