The Drop and reconnect of a large number of BT circuits was due to planned work: https://aastatus.net/42596
Lines are reconnecting, most are back online now.
We have four links to BT. Two in each of our London Datacentres. BT have overnight work that will take one pair of these links out of service and would be disruptive. Usually we are able to cleanly shut down these links to drain traffic off them. Tonight, we shut down one of the links without a problem, but shutting down the second did cause a large number of BT circuits to drops and reconnect. This was not the intent, and we've been able to move traffic like this successfully in the past. We do apologise to those who had their service interrupted this evening.
Lines should be back, many but not all are - we are investigating.
We restored one of the links we shutdown and this restored service for those who were still offline. This does mean, that when BT do their work a bit later, that there is a risk of another blip or possible outage.
Affected lines are back online. This post will be closed now - but refer back to the parent post for further updates of BTs work on 9th January in the early hours of the morning: https://aastatus.net/42596. The cause of this drop has been identified as a mis-configuration within BTs network which prevented our traffic from failing over to our links to BT in Telehouse. This has been fixed by BT and we will retest.