People often talk metaphorically about a glass ceiling being an obstacle to career progression but at the Citigroup tower in Canary Wharf the threat from above is all too real.
Since the building opened almost two years ago at least four glass panels, each more than a metre square, have fallen several floors to land in the lobby.
Citigroup says the glass that forms an atrium in the heart of the building is crumbling rather than hitting the ground in one piece, but that's not much comfort to visitors or staff.
Luckily each incident has occurred after working hours and no-one has been injured but the bank is sufficiently concerned to have called in glass consultants to try to cure the problem.
Apparently the glass has been breaking into small shards, which most likely stems from the way it was treated during manufacture. A Citigroup spokesman says: "We've put additional support along the top of the panels and a joint along each side to ensure they are held in place."
However on a recent visit Euromoney was warned not to venture too close to the panels for fear of falling through.