Police, ambulance and fire crews have been at the scene of a double-decker bus crash in Kennington Road, south London, in which a number of people were injured.
Two passengers who were trapped on the top deck of the bus have now been freed, London Fire Brigade (LFB) said. Two other passengers, including a 19-year-old woman remain in a critical condition.
The tree became embedded into the front of the bus and emergency services had to use specialist equipment to access one side of the vehicle.
LFB Station Manager Clive Robinson, who was at the scene, said the collision was a "particularly nasty" crash and crews worked in "very challenging circumstances" to get the passengers off the bus.
London Ambulance Service said they treated 32 patients who were sent to three London hospitals. Twenty-five, it said, were walking wounded with cuts and bruises. Five suffered more serious injuries, such as head and leg injuries.
Kennington bus crash
Kennington bus crash
1/10 Police, ambulance and fire crews are on the scene of a bus crash in Kennington Road, south London.
A number of people have been injured in the incident
2/10 The front of the top deck a bus which crashed into a tree is crumpled by the impact in Kennington, south London.
Around 23 people were injured, two seriously, in the crash according to the Metropolitan Police
3/10 Police, ambulance and fire crews on the scene of a bus crash in Kennington Road, south London
The force of the crash left the front of the bus crumpled
4/10 The front of the top deck a bus which crashed into a tree is crumpled by the impact in Kennington, south London
Emergency services rushed the scene to attend the injured
5/10 Police, ambulance and fire crews are on the scene of a bus crash in Kennington Road, south London
A number of people have been injured
6/10 Ambulance crews help a wounded girl off the London number 59 Bus which crashed on the Kennington Road.
The incident occurred around 10.50am on the Kennington Road while the bus was enroute route to King's Cross
7/10 Ambulance crews help the wounded from the London number 59 Bus which crashed on the Kennington Road
The vehicle collided with a tree, leaving the front of the bus crumpled
8/10 A members of the emergency services walks in front of a bus which crashed into a tree in Kennington, south London
Ambulances crews attended to the injured
9/10 Members of the emergency services attend to a bus which crashed into a tree in Kennington, south London
Some of the injured were rescued through the bakc window of the bus
10/10 Police, ambulance and fire crews are on the scene of a bus crash in Kennington Road, south London
Two people were seriously injured in the crash, according to the Metropolitan Police.
Two further patients – a man and a woman who were trapped in the bus – suffered serious leg injuries.
The bus was traveling on its way from south London to King's Cross in central London.
Mr Robinson said: "We used ladders to get some of the people out and in the case of the final two passengers trapped on the top deck crews had to shore up the upper floor which had started to collapse before using specialist cutting gear to release them. The man and woman were then lowered to the ground on a stretcher by firefighters on a turntable ladder.”
LAS Duty Station Officer Lee Hyett-Powell said: “There were a large number of patients for our staff to care for but all of the emergency services worked well together to ensure that they were assessed and treated as quickly as possible.
“We worked with the fire brigade to get to the two patients who were trapped on the upper deck. They had suffered the most serious injuries and were trapped on the bus for around two hours. We treated and stabilised them while they were being released before taking them to hospital.”
The number 59 double-decker "swerved to avoid another vehicle and struck a tree" at around 10.50am, Transport for London's director for buses, Mike Weston, said.
He added: "The incident took place on Kennington Road near the Imperial War Museum SE1."
The road is currently closed in both directions with routes 3, 59, 159 and 360 currently on diversion.
The vehicle is operated by Arriva.
Additional reporting by Press Association