A bus travelling through central London has had its roof ripped off after it hit a tree in a "freak accident".

Five people were injured when the Number 91 clipped the overhanging tree in Kingsway on Monday, sending the roof crashing into the road behind it.

Pictures on Twitter showed a double decker with upper-floor seats and handrails visible and its roof on the ground. One showed the bus in front of a tree with skinned bark next to a road sign that warned of "overhanging trees".

Speaking at the scene, London Fire Brigade's Euston station manager Gary Squires said those involved were "very lucky to escape serious injury".

"You can see the missing bark from the tree and the roof has come up and off the bus," he said.

"This is a very unusual incident. It is a freak accident."

Mr Squires said a man sitting on the top deck was left with a suspected broken nose while another passenger was taken to hospital with injuries to the side of their head.

Three others were treated at the scene and discharged.

London School of Economics student Ethan Meade, who posted pictures of the scene on Twitter, said he turned around after hearing a crash.

"I saw the roof fall down off the side of the bus, and the glass shatter everywhere. The passengers seemed to be sitting there pretty stunned as you'd expect," he said.

Transport for London said there would be a full investigation into the crash.