This is lifted from the BT forum as I'm not at home but matches my experience.
Primary DNS: 184.108.40.206 (OpenDNS) or 220.127.116.11 (Google DNS)
Tracing route to google.com [18.104.22.168] <- Incorrect BT IP address
BT default DNS:
Tracing route to google.com [22.214.171.124] <- Correct Google IP address
It is working for me and others have reported too that it works over 3/4G or if I use a VPN.
Edited by smouty (Fri 28-Nov-14 12:03:28)