The whole point of this is to get at access network ducting regardless of what it's meant for sollp. BT have minimal interest in VM's core network ducting.
It's debatable how much life there is left in VM's CATV network. In some areas it's a steaming pile of poop that hasn't been getting upgrades just analogue switch off and already cable operators are looking at migration strategies to FTTP and have for a while.
http://www.aurora.com/site/applications.an?li=a-fd
http://en.wikipedia.org/wiki/Radio_Frequency_over_Glass