New rules could be introduced at Tower Bridge after a bottle was dropped causing the top layer in the glass walkway to shatter.
The walkway opened to the public for the first time two weeks ago with the manager saying he was "gutted" about it smashing but emphasised the public was never at any risk.
The dizzying walkway allows you to see the river Thames more than 40 meters beneath your feet.
The glass was smashed last night after a bottle was dropped followed by a woman wearing stilettos standing on the crack.
But there are a further five layers of glass underneath.
"We are gutted it's happened in the first couple of weeks when it's been open to the public but it's completely safe.
"We should have said no glass on the glass section of the floor. It was a bit shortsighted of us."
The pane has been covered in a mat until it is fixed tomorrow night.
"The floor has five layers of glass with this sacrificial layer on top - it's there so we can replace it if it gets scratched.
"We are still open to the public and if we had any concerns we would have closed."
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