I was working on D'arblay street in Soho at the time and it was the shop owner below me who called the police. I remember smelling something unusual but thought nothing of it as I regularly get unusual smells wafting in the window as there is numerous restaurants in the street and the whores who work below me have all sorts of smells eminating from thier floor (there is nothing like the smell of jizz n jiff in the morning!).
I'd just come out of the outside toilet out the back (old buildings these!), and Tony who looks after DnC clothing below me was muttering about strange smells and coughing, i went back upstairs and carried on working, about half an hour later 5 fire trucks, 2 incident units with cameras and a scientific unit truck rolled up sirens blaring, I ignored them until i heard shouting from the street below. I went down stairs and a fire chief was in the street calmly telling people to evacuate. I went back upstairs and got my stuff and switched off everything, as i passed the whores on the way down one stuck her head out of a door and asked what was going on, I told her. I got out onto the street and everywhere was taped off, i found me colleagues at the end of the street and stood with them having a ciggarette, we watched the hot models evacuate the modelling place until we decided to go to the pub.
All this time there was no panic, with the emergency services doing thier jobs quietly without fuss. Some people were affected by the fumes, just coughing and nasal irritation. A few shopkeepers where getting irate about not be able to lock up their shops but that was the only trouble. Eventually the pub was evacuated, with the policeman getting booed! My boss told me to go home and the next morning the Thai restaurant across the street had a smashed in door. If it had been a proper terrorist attack we'd have stood no chance, we didn't panic enough!