As CityUnslicker has pointed out, the London Stock Exchane has gone into meltdown today quite literally. The computer systems for trading have gone for a burton. Basically they are doing there best to get it back.
My first thought when I saw this on Sky News earlier was "what about the Disaster Recovery suite in Habour Exchange?". I may be wrong on this now, but about six years ago I worked in Harbour Exchange at Canary Wharf, and two floors down from me was the LSE trading floor for these sort of emergencies.
I imagine the LSE is losing quite a bit of money today with trading so curtailed, but one has to wonder why, the minute they had been down for an hour, they did not iniitiate their DR plan. Maybe they don't have one anymore?