First of all - I hope the Queen goes back to good health. Seems to have been a good monarch over an extremely long period of time, which also included a ton of

First of all - I hope the Queen goes back to good health. Seems to have been a good monarch over an extremely long period of time, which also included a ton of technological and societal change. Second - "London Bridge is down". I can't help but wonder what happens if the actual, physical London Bridge experiences a catastrophic failure falls to the river. What's the codename for that event? "Escape London Bridge is down"? "London Bridge is down, literally, for real, no, I mean it"? "The Queen has climbed to the roof"?