Most ‘complaints’ about DV are that it’s dependent on the consumer’s own power supply, hence the incorrect assumption on my part, that your issue was related to this, after all a power cut is more likely to affect many customers over a large area, and be considered by both the ISP and Ofcom.
If you had significant cable pair fault on the current legacy PSTN ( public switch telephone network) then it’s entirely probable that telephony would be lost , in that respect someone in your position would be no worse off on DV , a chance that service will be unavailable.
There is no reason why a VOIP service is more likely to fail than POTS ( plain old telephony service ) and because there is no mitigation against a copper pair failure, then why would there be any mitigation mandated just because the telephony is now VOIP ?, any individual could suffer an individual loss of service on POTS or VOIP, that would be unfortunate for the individual.
Any individual line in the grand scheme isn’t particularly important, the provider that supply’s service over it will no doubt have some compensation scheme if it’s out of order , a catastrophic failure ( like a ‘FTTC’ cab being destroyed by a road traffic accident ) could well knock out services that rely on it, but a copper pair cabinet could also suffer in the same way , so it’s really of no relevance that if broadband goes off and telephony also goes off with it.
BT probably mention this , more to alert users to the difference, after all some consumers turn off the router when it’s not in use, they may not realise that would affect telephony, and at the moment in a power cut the phone will continue to work , but obviously without a UPS won’t, hence the advice that a mobile may be useful in these cases, but obviously not for those without a mobile signal, and without seeming flippant , if someone on DV without a mobile , or has a mobile but no mobile signal , and is sufficient worried during a broadband outage that being unable to use the phone is unacceptable, then the advice would be to move to somewhere that has a mobile signal.
BT don’t have any duty to ensure that in all circumstances you can make a phone call
