Two people are currently trapped and more than 50 have been injured after a tram overturned in south London, the city’s fire brigade has said.
Crews freed a number of people but two remain inside the tram, which derailed in Croydon just after 06:00 GMT.
Transport for London (TfL) said the incident, involving a two-car vehicle, happened on a bend inside a tunnel, near Sandilands Tram stop.
The Met Police described it as a “serious incident” and have confirmed that they have arrested the Tram driver.
They have also confirmed that there has been “some loss of life”, but have yet to release any more information. Local news reports suggest as many as six people are feared to have been killed.
Hannah Collier, who lives nearby the incident site, said she heard “a big crash” and saw people being carried away on stretchers.
Ms Collier said: “I was in bed watching the election when I heard a big crash, which I thought was the wind.
“Then I heard people shouting and then the emergency services arriving.
“Later I saw at least one person being brought out on a stretcher.”
The Tram began operation in May 2000 as Croydon Tramlink, becoming the first tram system in London since 1952. More than 27 million passengers used the service in 2015/16.
The Rail Accident Investigation Bureau is investigating the derailment.