On a 0.3 Mb/s you'll be downloading at around 35KB per second. that second page of pics I sent you would take around 2 minutes 40 seconds to download before it would display the page.
Either someone in your house is downloading stuff and taking all your bandwidth (Kids will always say they aren't lol) or there's something seriously up with your internet connection
Are you in a remote area ? Far from your local phone exchange ?
Try the same test making sure no other computers are on in the house. Also, if you're connecting via wireless try plugging it in via the ethernet cable.
Sounds like you need to get Virgin to send an engineer out and check it properly.