We're investigating problems with BT lines not able to connect. This will only be affecting BT lines that have disconnected and are trying to reconnect recently.
Customers affected by this will be be able to PPP connect, but they will be caught by BT and given a 10.x.x.x address. We are investigating the problem.
A configuration problem at our side has been found and fixed. We suggest customers turn off their router/modem for 2 minutes and try connecting again.