A bus driver has died and 15 people have been injured in a crash involving two buses and a car.
Kenneth Matcham, 60, died at the scene after a car and two single-decker buses collided in Orpington, in south-east London, on Thursday night.
The 24-year-old driver of the car has been arrested on suspicion of causing death by dangerous and drug driving.
The Met Police said of those hurt, three people had serious injuries while the rest were minor.
According to one witness, the crash happened at the bottom of The Avenue at the junction of Park Avenue and Sevenoaks Road.
The London Fire Brigade (LFB) sent 60 firefighters to the scene of the collision, which happened at about 22:15 GMT.
"Firefighters rescued several casualties from the buses and immediately undertook first aid, being joined by colleagues from London Ambulance Service," its assistant commissioner Graham Ellis said.
Claire Mann, TfL's director of bus operations, offered the firm's condolences and sympathies to Mr Matcham's family and confirmed they were working with the bus operator GoAhead and the Met Police to "ensure we find out what happened".
Counselling has also been made available to those affected by the crash, she said.
GoAhead tweeted that it was raising money on a crowdfunding website to support Mr Matcham's family.
One witness, who did not wish to be named, said he was in his living room when "we literally heard a loud bang".
"It didn't sound like a car crash, it was a really weird noise," he said.
"I went out to take a look and saw the carnage. My son is 11 and he was really upset. We didn't really want to stay outside as it was too upsetting really."
He said one of the buses had gone into a front garden.
"My heart goes out to those involved. Very distressing," he added.
Another resident, Tariq Sheik, said he heard "an awful lot of ambulance and fire engine noises last night" and thought it might have been connected to Halloween.
"Horrific scenes, it's not very pleasant," he added.
Road closures are in place around the area and police have advised motorists to use alternative routes.
Six bus routes have also been diverted.
Detectives have appealed for any witnesses or anyone with dashcam, mobile phone or CCTV footage of the collision to contact them.