London attack – as it happened: Theresa May raises threat level to critical as Isis claims responsibility

Soldiers to support police after 29 people are hurt in tube bombing at Parsons Green

Parsons Green attack: What we know so far

The UK's terrorist threat level has been raised to critical after London was hit by a new terror attack as commuters headed to work on the Tube.

An explosion at Parsons Green underground station in the west of the capital injured passengers and led to a "major incident" being declared. Yet more people were hurt during the crush to leave the train, witnesses said.

Images shared online appeared to showed a bucket with wires trailing from it smouldering inside a District Line train.

The device is being forensically examined while detectives are scouring CCTV and examining witness statements for potential leads.

Armed police, paramedics and firefighters were all called to the scene.

Witnesses described flames and a "fireball" following the incident at about 8.20am today.

Assistant Commander Mark Rowley, who is the UK's top counter-terrorism officer, said the force continues to "chase down suspects" in connection with the attack.

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Key Points

• Explosion at London Tube station leaves 29 injured
• UK terror threat level increased to 'critical', the highest level
• Met deploys extra 1,000 armed officers to hunt terror suspects on the run
• Isis claim responsibility for attack
• 'That could have been me': Parsons Green residents try to process local bomb attack
• Police dismiss Donald Trump terror suspect claim, saying 'we don't even know who the suspects are'

[15 September 2017 09:48 · Andrew Griffin]

Aerial shots on Sky show people being escorted out of the train, which is still at Parsons Green station. 

[15 September 2017 09:53 · Andrew Griffin]

Helicopters are now over the train, and show that it appears to be entirely act from the inside. It also shows people being walked off the train and along the side of the tracks.

[15 September 2017 09:57 · Andrew Griffin]

This from Lizzie Dearden, our reporter on the scene:

Police are still extending cordons around Parsons Green Tube station and say they are also evacuating all homes within 100 metres. A school just behind the station is on lock down and children are being kept in a hall

[15 September 2017 10:03 · Andrew Griffin]

Downing Street said Prime Minister Theresa May was "receiving regular updates" on the situation at Parsons Green.

[15 September 2017 10:05 · Andrew Griffin]

Sylvain Pennec, a software developer from Southfields, near Wimbledon, was around 10 metres from the source of the explosion when fire filled the carriage.

"I heard a boom and when I looked there were flames all around," he said. "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."

[15 September 2017 10:05 · Andrew Griffin]

The train had "lots of school children on board", according to the BBC's Steve Swann.

[15 September 2017 10:18 · Andrew Griffin]

from Lizzie Dearden:

Local residents are gathering at police cordons around Parsons Green Tube station after being evacuated from their homes. Gautam Krishna, 42, is waiting for his children to be let out of a school inside the area on lock down.

He tells The Independent: "They have locked the girls in the school hall, apparently police are doing a sweep.

[15 September 2017 10:19 · Andrew Griffin]

The incident is a terror attack, police have confirmed.

[15 September 2017 10:22 · Andrew Griffin]

From Lizzie Dearden:

Kate Capilupi, 35, is waiting to get back inside her home with her baby son.

"I was walking my daughters to school when we heard the news," she says.

"I got back home and there was a police officer at my front door.

"He told me there had been an incident on the tube and I couldn't go in."

[15 September 2017 10:25 · Andrew Griffin]

Prime Minister Theresa May is to chair a meeting of the Government's Cobra emergencies committee this afternoon to discuss the terrorist incident at Parsons Green.