BBC News 24 and BBC World began rolling live coverage of the terrorist attacks just before 2 pm yesterday, shortly after the first plane crashed into the World Trade Centre in New York.
By 2.10 pm BBC1 had switched from its usual afternoon schedule to simulcast News 24's output.
Said Richard Sambrook, Director of BBC News On the US disaster: "I doubt many of us have ever been confronted with a story of such magnitude. Despite the shock and horror we all felt, I was proud of the superb response from our teams who worked round the clock to provide audiences with measured and authoritative coverage."
"This is the largest extended live news coverage we've had on BBC1 since Princess Diana's death," BBC head of TV news, Roger Mosey, said. "I can't think of anything on this scale in the past 10 or 15 years. One of the Ten O'Clock News editors said that our lives won't be the same every again after this. At a banal level it's a massive, massive news story."
BBC World has been broadcasting live continuously since news first broke yesterday afternoon (just before 1400 BST)..
BBC reporter Stephen Evans, was at the centre of the deadly attack. Evans, the BBC's business and economics correspondent in north America, was sitting in the foyer of the World Trade Centre as the two aeroplanes crashed into the twin towers in the worst terrorist attack ever.
"I was on the ground floor of the building sitting in a chair waiting for somebody to turn up as you do. There was huge bang. There was a huge bang."
"It felt to me like somebody dropped a skip full of rubbish, a great container full of rubbish from a great height in the yard which separates the two huge towers which are the World Trade Centre.
"The building physically shook. It's one of those where you think, well something's happened on a building site. That's the way it is. But seconds later, there were two or three similar huge explosions and the building literally shook. You literally shook at the base of this building. At which point, people came - I nearly said screaming, but they weren't screaming - it was a mild panic. People simply saying, 'get out of here, get out of here.' People streaming to the other side of the building. At which point smoke appeared everywhere as if a mist had suddenly settled on the building. We all streamed out, some people running, some people crying, nobody really screaming. We crossed the road and you look up and you can see the top of one of the towers, smoke billowing out from it, the odd flame coming out of the top of these towers - pretty well the highest buildings in the world.
Everybody then got calm, simply looked up and the authorities moved them further and further away. About, I would guess - time is very difficult to judge in these circumstances - but I would guess five minutes later there was another explosion half way down the second tower and that then looked rent, almost as though a child had knocked into a toy, something like that.
And again, smoke started billowing out of that second building. I don't know what the cause was. Everybody I think initially assumed it was a bomb, but then people kept coming past me saying "No. No. it was a jet, it was a jet".
Whether it was one or two I simply don't know. I'm now in a hotel about 100 yards from the building. Buildings in this area are being evacuated. People are streaming away. No one is saying very much, actually, because they are shocked as you would expect them to be. People simply don't quite comprehend what's happening. You can hear the shaking in people's voices as they say, "what's going on? What's gone on? I don't know." And people are nodding at me now as I say that.
The cause, I can't illuminate. All I can tell you, is it was a very frightening experience, but people by and large reacted very well to it."
