This is what Virgin has to say about traceroute failing within its own network:
However, taking this caveat into account, if you cannot access a particular website through a browser AND a traceroute is failing to get to it, the last hop will likely be the point at which there is the problem.
If this address is one of our machines [it will have cableinet in its name], then we should be able to do something about it. This means that the failure is within our network. If you contact our technical support team they will be able to escalate the problem to our networks team to investigate.
Read it
http://help2.virginmedia.com/help/ge...internet_trace