Pictured: White bucket being probed as source of Underground explosion
A picture being circulated by witnesses and news agencies following this morning's explosion on a London Underground train at rush hour has been described as a "builder's bucket".
The item, which was apparently left smoldering in the carriage after people evacuated the train in a panic, appeared to be wrapped in a Lidl supermarket bag and is said to have wires coming out of it.
One eyewitness who captured a video after he left the carriage said he believed the item 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."
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."
Witnesses on board the train said the explosion created what they described as a "whoosh" sound and it was described as a "fireball" which moved up the train.
Scotland Yard has said there was an explosion on the train as a result of an IED device on board the tube.
A detailed investigation at the scene is underway.