Wednesday 7 March 2012 2.18pm
First of all - check your speed by clicking here
If it is slow, try simple stuff like rebooting your ADSL modem. Mine has gone wonky a few times (I have Netgear DG834GT) and a reboot sometimes fixes it.
If still no good - check the connections to your filter and the BT socket - reseat the connections (unplug and refit them).
If still no good call Virgin - they can do some tests their end to confirm the exchange.