It's a shame that these businesses that have so much hinging on their Internet connections don't have any kind of backup line arranged.
Edit: you could also consider a backup line from an LLU provider. You still have the copper as a single point of failure, and perhaps power at the exchange, but the infrastructure is different.
While BT runs over telephone wires. Therefore is more pervasive in the UK.
When I spoke to a support guy yesterday he said that 30% of their network was out and this was 4 hours into the outage.
So Roy works at BT now!
Edit @ 13:50, back up, but so slow it's making doing anything impossible, still routing through DR site