What a nightmare, but if done right could mean some major pressure for BT Retail / Business.
What a nightmare for B Sky B:
Sky lock down their routers. TalkTalk let you use your own.
Why it could be good for B Sky B:
Increased network capacity
New subscriber up sell potential.
Traffic management experience
IPTV experience (Tiscali TV was a true implementation).
I've worked at Tiscali (Freedom2Surf, Nildram, Pipex Business), V Networks (TalkTalk Business) and B Sky B.