As soon as I heard the bang, I knew it was a bomb. Thunder doesn't sound that brutal or shake the building like that. At the time I was in a meeting room in BMA House with a visitor to the BMJ. “That's a bomb,” I said, as my visitor and I leapt from our seats and ran out into the main editorial office. Everyone was rushing to the balcony to see what had happened. Even before I got close to the edge I knew from the contorted expressions etched into the faces of my friends and colleagues looking down on to the street two floors below that it was something horrific. Some of them were wailing. I peered over the edge for an aerial view of a most sickening scene. The roof of the crippled bus—the number 30 that was destroyed in a terrorist attack in Tavistock Square last week, right outside BMA House—had …