On the evening of 19th May a small number of lines all in the Guildford area (GU postcodes) were offline between around 21:35 and 21:55. This only affected TalkTalk connected circuits. We'll investigate the cause of this with TalkTalk and will update this post shortly.
TalkTalk have confirmed that they did have a major network outage. This was resolved by TalkTalk rebooting one of their main BRAS aggregation devices. They do apologise and have raised the problem with their vendor.