In the firing line

Henrietta Bredin goes backstage at the Royal Opera House and finds a stash of weaponry

I am standing outside a heavily reinforced metal door somewhere in the furthest flung recesses of the labyrinthine corridor-tangle backstage at the Royal Opera House. A painted shield has the word Armoury picked out on it in gold lettering and next to a no smoking warning is a sign saying ‘No trespassing.