You need one of these, although I'm not sure if the hub supports pulse rather than tone dialiing - you could just connect the phone and see if it works! (Also assuming that your phone has a BT plug attached and wasn't "hard wired" into a junction box)
It needs to be connected to the uppermost phone socket on the hub.
Have you got a landline service from Virgin? That needs to be active on your hub before you can plug a phone in.
If you log into your hub you should see this on the welcome page with telephony "ready" (if you're in router mode then same applies and wifi will likely show as enabled also - my hub is in modem mode but telephony works in either router or modem mode):
my router is set up for telephony and I already have a more modern phone plugged in.I just like the look and feel of the old dial phones. I have plugged one in and I have a ring tone and can dial out, it just doesn’t ring when you call the home number. Thinking my old phone may be defunct and I might need a new old phone or there is a connection missing somewhere in the wiring