Shocking pictures from the scene showed the roof torn from the 91 route bus, with glass scattered across the road.

It is thought that the bus, which normally runs between which runs between Crouch End and Trafalgar Square, struck a tree just outside King's College.

Five people were injured in the accident.

Two people had to be taken to hospital with facial injuries, while another three were treated at the scene.

A London Ambulance Service spokesman said: "We treated five patients. We treated two patients for facial injuries, they were taken to St Thomas's Hospital.

"We treated two patients for minor injuries, they were not taken to hospital.

"We treated another patient for a knee injury. This patient was discharged at the scene."

The London Fire Brigade said on Twitter: "We are at the scene of an accident on #Kingsway Holborn. A bus has lost its roof. Thankfully only minor injuries."

At the scene London Fire Brigade station manager Gary Squires said: 'Those involved were very lucky to escape serious injury.'

Lauren Leonard, who witnessed the aftermath of the accident, told the MailOnline: "Everyone was huddling round so it must have happened just before I went outside.

"We are all so confused, because people are saying it hit part of a tree, but the tree didn't seem damaged at all.

"No one can get down the street. I saw a guy being treated for a bloody nose and another being treated for shock.

"You never want to get on the top deck of a double decker again - I have never seen anything like it."