Victims of the Croydon tram disaster have had limbs amputated, police have confirmed.
Tearful mourners have left tributes and dozens of flowers near Sandilands tram stop in Croydon where the two-carriage vehicle derailed and overturned early yesterday morning.
Seven people were killed, one of whom is believed to be a young child, and 50 injured.
Survivors said the tram driver may have "blacked out'' at the controls. Others compared the crash to a "horror movie'' and said one man had been decapitated.
Injured passengers were taken to St George's Hospital in southwest London and Croydon University Hospital.
A police source said: "We've got some victims with amputations, including a leg and an arm.
"Another had a collapsed lung. The patients at St George's are all over the place in different wards.''
A St George's Hospital spokesman said three three victims of the tram crash have had surgery and are being looked after by surgical and medical teams.
British Transport Police said formal identification of the dead was going to be a "lengthy and complex'' process, but revealed that of the seven victims, six were men and one was a woman.
Residents said the Wimbledon-bound tram was coming down a steep slope towards a bend when it carried on down the hill rather than turning.
It tipped onto its side at the entrance of a tunnel, throwing one person through a window, according to survivors.
British Transport Police Assistant Chief Constable Robin Smith said officers had been carrying out "painstaking forensic examinations'' since the crash.
He added: "There's always an element of mystery and of course people are craving to know what happened.
"But to understand what conclusively happened here will take many months.''
A statement issued by British Transport Police on Thursday evening read: "We can confirm that six men and one woman have sadly died.
"We are working with the Coroner to identify these seven people and their families are being supported by specially trained officers."
Meanwhile, the first victim of the Croydon tram disaster was named as 19-year-old Dane Chinnery, a labourer and Crystal Palace fan who was described as "lovely, caring and beautiful'' on social media.
His friend Tom Dale, 20, who was also on the train, said he looked for Mr Chinnery after the crash but "all he could see of him was his boot".
Dale, who went to Addington High School with Chinnery and took part in performing arts with him, said they were on their way to work.
He said that after the tram crashed he was looking for his friend, and asking, "Where's Dane? Where's Dane?", but he could only see his shoe where he had been sitting.
"It was like walking out of a war zone,'' the chef said.
Dale, who was badly bruised, said of Chinnery: "He was just a friendly, genuine lad, did no harm to nobody really. No one deserves for this to happen to them."
Chinnery, who worked as a labourer at environmental services firm Hydro Cleansing Ltd, according to social media, was described as a "helpful and funny'' person in online tributes.
Chinnery's parents were too distraught to speak about their loss but his uncle Trevor Corps told the Croydon Advertiser: "He was someone so, so special to me and my partner, [he was] like all my nephews and nieces are, but Dane had that extra magnetism, he was always smiling, always happy.''
A large group of about 20 people bearing roses cried and hugged each other at the scene as they laid their floral tributes and wrapped a Crystal Palace scarf around a post. Schools, businesses, residents and Crystal Palace Football Club have been among those to pay tribute to the victims and leave flowers.
Crystal Palace FC, based in the Croydon borough, released a statement today paying tribute to the victims.
A spokesman said: "Everyone at Crystal Palace Football Club was shocked and saddened
to hear about the tragic tram accident on Wednesday morning.
"We understand that at least one of the victims, 19 year-old Dane Chinnery, was a Palace fan.
"Our prayers are with his family and with all the friends and relatives of those victims that have been affected.
Chinnery's friends and Palace fans are trying to organise a minute's applause on the 19th minute of the upcoming game against Manchester City through social media.
Chinnery's former headteacher Martin Giles, of Meridian High School, New Addington said: "The staff and students at Meridian High School have been heartbroken this morning to hear that a former student died yesterday.
"We have extended our deepest sympathies to the family and do so to the wider community, who have all been so affected.
"To our knowledge, at least three other former students have also been injured."
Local residents have spoken of noticing the "stillness'' in the area today instead of the usual hustle and bustle.
Survivors spoke of the terrifying experience they endured after the train derailed, including flipping over three times.
Passenger Taiye Ajibola told ITV : 'I thought he [the driver] was going to stop but he couldn't so he increased the speed. As soon as we got towards the end he increased the speed and it somersaulted one, two, three and he landed at the other side.''
Ajibola, who suffered head injuries, described how he saw someone trapped under the tram who shouted: "I'm still alive, don't step on me."
Rui De Sa, a builder on his way to work when disaster occurred at 6.10am, said: "One man beside me was screaming and had his arm trapped outside the tram as it skidded along on its side.
"The man next to him had his whole head out of the tram crushed underneath. I can't get that image out of my mind.''
He added: 'I was on my phone with my headphones on then we just heard screaming in the first carriage. That toppled over then we went over. It went black and we were all just thrown around. People were screaming and shouting for help.
"Everyone was trying to get hold of a mobile phone to call loved ones.''
De Sa, who suffered back and shoulder strains, was in the tram for 50 minutes before being freed.
He described the crash as something out of a "horror film''.
He added: 'It was going too fast round the bend. I've been getting that tram for nine years and normally you feel it braking there. This time I couldn't feel it braking at all."
De Sa said once the train was on its side anything it hit was "like a blade'' through it.
Several survivors were trapped in the wreckage, and a large team of emergency workers battled for hours to free them and ferry the dozens of injured to hospitals across the capital.
The Rail Accident Investigation Branch said the tram derailed as it was negotiating a "sharp, left-hand curve'' with a speed limit of 12mph (19km/h). A spokesman said: "Initial indications suggest that the tram was travelling at a significantly higher speed than is permitted.''
Father-of-four Martin Bamford, who was on his way to work when the tram turned over, said: "When we were coming through the tunnel we were going at some speed and the tram was speeding up more and more. We hit the bend way too fast and the tram flipped. The tram was full mainly of people going to work.
"There was a girl who was on top of me and she did not look very much alive at all. She was bleeding all over the place and I don't think she made it.
"People had broken legs and head injuries. When it flipped everything went flying, people were on top of me.''
Bamford, a cleaner, who was taken to Croydon University Hospital for treatment, added: "There was blood everywhere and belongings and shoes. It was absolute carnage. I just can't seem to get it out of my head, it just keeps going over and over again.
"I looked around and there was just blood everywhere I was shouting through to the driver to ask him if he was okay. He was laying on his side and I asked him if he was okay. I think he was in his mid 30s or 40s.
"When we got out I asked the driver if he was okay and what happened and he just said to me 'I think I blacked out'."
He added he thought the tram "may have been travelling up to 70mph'' around the bend, which 'normally would be taken at six or seven mph''.
A passenger on a tram travelling on the same stretch of track last week, told how he was left shaken after he claimed it "lifted onto one side''.
Andy Nias wrote on Facebook that he and 29 fellow travellers feared the worst when their tram "took the hard corner to Sandilands at 40mph''.
He said on October 31: "Oh mate...30 of us on the tram this morning and we all thought our time was up...tram driver took the hard corner to Sandilands at 40mph!!
"I swear the tram lifted onto one side. Everyone still shaking...it's mad."
In February 2012 a tram, carrying 100 passengers, also derailed on the line but no one was hurt. The accident happened about half a kilometre from this week's fatal crash.
Peter McKenna, Deputy Director of Operations at London Ambulance Service said it sent 22 ambulance crews, 12 officers, and two advanced paramedic practitioners to the scene, along with a hazardous response team, two trauma teams from London's Air Ambulance and a command support vehicle.
"We treated a number of patients at the scene and took 51 patients to hospital. Twenty were taken to St George's University Hospital and 31 to Croydon University Hospital."
A spokesman for St George's Hospital said: "Twenty people have been brought to St George's Hospital in Tooting for treatment. Of these 20 patients, four are seriously injured. All patients are being cared for by our clinical teams."
Three people were released from the wreckage by 11am and 70 firefighters at the scene battled to free two more for hours.
Lesley Purnell, from Croydon, said she had a long wait after she tried to find out the condition her injured husband was in at St George's Hospital.
She said: "I finally managed to get through to a nurse and she brought my husband to the phone.
"He is badly concussed and in shock, but he is okay.
"I never cried so much when I heard his voice - I am devastated for all those involved and have lost their lives."Thirty-one people taken to hospital were transferred to Croydon University Hospital.
The tram derailed where the New Addington branch of the tram line meet the Beckenham and Elmers End branches.
Police confirmed the 42-year-old driver, from Beckenham, had been arrested on suspicion of manslaughter. He has since been released on bail.
A witness described the moment he was arrested by officers, detailing how he had "emotional pain all over his face''.
The tram crash in Croydon is one of the deadliest in recent British rail history.
Seven have died and there are fears the toll will rise.
It is believed to be the first tram crash involving fatalities since 1959, when two women passengers and the driver died after a tram caught fire in Glasgow following a collision with a lorry.
It is one of the worst rail disasters in the past 15 years since the Great Heck rail crash of 2001 in Selby, North Yorkshire, in which 10 people died.
Seven people died in the Ufton Nervet rail crash in Berkshire in 2004. A First Great Western passenger train from London Paddington to Plymouth collided with a car on a level crossing.
Seven people were killed in the Potters Bar crash in Hertfordshire in 2002, which happened when a West Anglia Great Northern train travelling from King's Cross to King's Lynn in Norfolk derailed at high speed.
The four-carriage train was moving at 97mph when it hit a set of points near Potters Bar Railway Station that moved, causing the rear carriages to derail and the last carriage to flip into the air.
The worst rail disaster in recent history was the Ladbroke Grove crash in London in 1999, when 31 people died and more than 520 were injured.
Parnia Abbasi and her family were killed in an Israeli strike in Tehran.