Terrified passengers described seeing victims covered in blood as people scrabbled to evacuate after an explosion on a London Underground train.
Commuter Peter Crowley suffered burns to his head after flames swept through a packed carriage at Parsons Green station on Friday morning.
“A fireball above my head has come and singed all my hair,” he told BBC News.
“I’ve got burn marks on the top of my head and everyone just ran off the train – it was quite scary.”
Sylvain Pennec, a software developer from Southfields, near Wimbledon, said fire filled the carriage.
“I heard a boom and when I looked there were flames all around,” he said.
Explosion at Parsons Green Underground station (PA Graphics)
“People started to run but we were lucky to be stopping at Parsons Green as the door started to open.”
He described the scene of panic as commuters struggled to escape the carriage, “collapsing and pushing” each other.
Mr Pennec stayed behind to take a closer look at what he believed was the source of the explosion.
“It looked like a bucket of mayonnaise,” he said.
“I’m not sure if it was a chemical reaction or something else, but it looked home-made. I’m not an expert though.”
Media technology consultant Richard Aylmer-Hall, 53, was sitting on the service bound for central London when panic unfolded at around 8.20am.
He said he saw several people injured, having apparently been trampled as they tried to escape.
He told the Press Association: “I was on the Tube, we had just stopped at Parsons Green, I was on my way up from Wimbledon towards Paddington and suddenly there was panic, lots of people shouting, screaming, lots of screaming.
“It was an absolutely packed, rush-hour District Line train from Wimbledon to Edgware Road.
“I saw crying women, there was lots of shouting and screaming, there was a bit of a crush on the stairs going down to the streets.
“Some people got pushed over and trampled on, I saw two women being treated by ambulance crews.”
Aaron Butterfield, a production manager, said he saw people “crawling over one another” in panic as they tried to get out of the station.
He added: “People weren’t even running, they were literally crawling over one another and just fleeing I guess.
“It’s been really frightening and very confusing especially as no-one really knows what’s going on.”
Chris Wildish, who was on the train, said he saw a “device” in the last carriage.
“It was a white bucket, a builder’s bucket,” he told BBC 5 live.
“Flames were still coming out of it when I saw it and had a lot of wires hanging out of it – I can only assume it was done on purpose.
“It was standing against the door of the rear-most carriage.”
BBC News presenter Sophie Raworth, who was at the scene, said she saw a woman on a stretcher with burns to her face and legs.
She added: “Her legs are wrapped up and she has burns.
“She had burns to her face – she’s conscious, she was taking oxygen and pain relief as well.
“She seemed to have burns all over her body from top to toe.”
A director of Ride Republic, an exercise studio near Parsons Green station, said armed police led an evacuation of his building.
Around 15 to 20 people were rushed from a cycling spin class, he said.
He said: “We had one client come back to our studio after a class at around 8.25am and she said there had been a terrorist incident, she was quite shaken up.
“Our front of house staff took that in and closed and locked the door.
Explosion at Parsons Green Underground station (PA Graphics)
“Within 10 minutes three or four police cars arrived outside the studio.
“A staff member went outside to check if we should leave and then another police officer came in and said we need to leave now.
“Someone from the front of house came into the class, which had the music going, and said ‘shut off the music’.
“It doesn’t really bed in at that time, people weren’t expecting that in Parsons Green.
“I don’t think anyone was too panicked.”
Ryan Barnett said he heard of victims with burn injuries and reported seeing some commuters taking selfies on the platform.
The 25-year-old, who works in politics and had been travelling to his office, told the Press Association: “I was lucky, I wasn’t in the carriage, I was in a few carriages down but I was caught up in the stampede down the stairs.
“I was sitting there, headphones in, at Parsons Green, the doors open fine, I’m not really paying attention and all of a sudden hundreds of people run past me screaming a mixture of ‘stampede’, ‘attack’, ‘terrorist’, ‘explosion’, ‘get off the train’, ‘everyone run’.
“Parsons Green station has a staircase at the front of the carriage where the train pulls up – I’m running and keeping my head down because there might be gunfire and on to the staircase.
“But when I was on the staircase, the stewards and other passengers, they are shouting ‘stop, stop, stop’, so I ended up squashed on the staircase, people were falling over, people fainting, crying, there were little kids clinging on to the back of me.
“It is absolute chaos, it was quite scary because at one stage we thought we might be trapped there – I heard a pregnant woman lost her shoes and had fallen over.”