There appears to be a problem with one of BT's BRAS's (21CN-BRAS-RED3-BM-TH) where customers are unable to connect. We are speaking to BT about this now and will update this post ASAP.
BT 'tech services' are aware and dealing as we speak ....
There are engineers on site already!
WOW. BT have fixed their BRAS fault in record time. :)