Thanks for the info,.....However does that mean that at the time of the alarm being sounded,all the relevant controllers on each LHR frequency send out a message,or is it all automated to some degree??
No automation. The controller on the departure runway (27R) simply said words to the effect of, "All aircraft standby, there is a fire alarm sounding in the tower." He then came back to say that all departures were suspended and that the tower was being evacuated. He left us with the words "Heathrow service now closed" (or similar).
The silence was bliss & we had a lovely cuppa after shutting the engines down etc.
About 25 mins later the world came alive again - we received info on the tower freq. & from our company freq. that the tower would be up & running again in about 10 mins (they had to switch all their kit on again) which gave us plenty of time to wind up the elastic band again & prepare to go. The controller then came on & started putting his big jigsaw back together & off we went.
In my view the folk in the tower handled the situation very well.
One suggestion might be that they have some handheld radios that they can grab on the way out during an evacuation so that they can broadcast a 'situation update message' to the aircraft that are still on the ground.
edit - typo