I could certainly send you the list of all ntl's current prefixes (Paul M FYI if the rest of us didn't know ntl's current blocks we'd have a lot of trouble knowing how to route stuff to them, there are lists on RIPE and a simple command on a peering router gives them all as well.) however just the list for your area would make far more sense.
http://www.ripe.net/
Pop your IP address in there and it should show the IP addresses being used in your area.
BTW The full list isn't that large, apparently only 148 prefixes.