Check out tfl.gov.uk they've got a great picture of the underground symbol COVERED in snow. You can also check out there how much of the transport system is down: pretty much everything! The buses, most of the train system, nearly all of the underground (Except, oddly, the Victoria line- maybe it is the only entirely covered line?) and taxis aren't really running either.
I'm at work- the only people who made it in are the management, nearly all the people who work hourly, and the only self employed physio...
I'm really hoping I don't have to walk home all the way home, but if I do I've got my clogs that got me through Michigan winters, two pairs of woolly socks, some food, my snazzy new gloves that *actually* keep my hands warm, the warmest sweater I own, etc., etc.
13:00 Update: The weather continues to be silly, but the two underground lines I need to get home are currently operating "good service" and "minor delays" which is pretty much the best of the bunch. Whew.