According to an article I read ages ago (and I based
http://www.cableforum.co.uk/article/...alogue-turnoff upon), virgin *are* planning to upgrade some areas to digital. At the time of writing that article (and now, actually), I have no idea of which areas they will upgrade.
I suspect they are currently in the process of surveying the various networks to see what hardware needs upgrades, and whether it is viable to do so.