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.

Please allow a moment for the liveblog to load.

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 20:55 · Kristin Hugo]

Assistant Met Police Commissioner Mark Rowley says the investigation is making "excellent" progress and was "fast moving". 

He said the remaining parts of the bomb had been made safe.  

The public should expect to see additional an additional armed police presence, stop and searches, and road checks. 

[15 September 2017 20:56 · Kristin Hugo]

Mr Rowley says around a thousand armed police officers have been made available because of military support. 

He urged the public to stay vigilant and to "act on their instincts". 

[15 September 2017 20:57 · Kristin Hugo]

No further detail is being given around the suspect, Mr Rowley just says the investigation is moving fast and has covert elements.

Police are being "open minded" about him and his potential associates. 

[15 September 2017 20:58 · Kristin Hugo]

Police are only aware of one explosive device, which is being examined by forensic experts, Mr Rowley says.

[15 September 2017 21:01 · Kristin Hugo]

Police have been trawling through masses of evidence. Mr Rowley said hundreds of officers have been trawling through CCTV and taking statements from tens of witnesses. At least 77 images and videos from the scene have been handed over to detectives, he added.

[15 September 2017 21:08 · Adam Withnall]

[15 September 2017 22:05 · Adam Withnall]

Unsurprisingly, the attack has dominated the front pages of tomorrow's papers: 

[15 September 2017 22:31 · Adam Withnall]

Meanwhile the Sun leads on an unsubstantiated claim that there is a second bomb.

Assistant Commander Mark Rowley, the country's head of counter-terrorism policing, said the police were "only aware of one bomb"

[15 September 2017 22:32 · Adam Withnall]

While the i and the Guardian lead with front page pictures of the victims

[15 September 2017 22:42 · Adam Withnall]

Scottish politicians have offered their solidarity to London on Twitter: