Shortly after midnight last night, one of our institutions experienced what looks like a massive distributed denial of service attack against multiple hosts on their network. After a fair bit of analysis it looks like this attack was exceeding the 15gigabit/second mark into the London router. Normally this would result in severely congested international bandwidth though things should keep working (other than for the affected institution who would probably be experiencing degraded service on their internal network)

Unfortunately, one the devices in the network used to control international bandwidth picked up this attack and decided to shut down certain pipes for a duration to "protect" the network. This resulted in actual international outages rather than just heavily congested circuits.
The attack ceased at around 5am this morning and the network seems to have been stable since then.