Image source, Reuters

We're pausing our live coverage of developments after a taxi exploded outside Liverpool Women's Hospital on Sunday.

As the fast-moving investigation continues:

• Police declare it a terrorist incident and say the passenger in the taxi detonated a homemade device
• A fourth man is arrested and detained under the Terrorism Act
• It follows the arrest of three other men in the Kensington area of the city
• The driver of the taxi, named locally as David Perry, is praised for his bravery
• Boris Johnson chairs a meeting of the Cobra emergency committee

Updates were brought to you by Tom Mullen, Lauren Hirst and George Bowden.

Read our latest story here.

Police have said there is no intelligence to suggest any wider threat to the area as forces seek to reassure residents following Sunday's explosion in Liverpool.

Greater Manchester Police has been assisting Merseyside Police in the investigation, alongside Counter Terrorism North West.

Assistant Chief Constable Mabs Hussain said: "I think it is important to stress that there is no intelligence to suggest that there is any direct threat to Greater Manchester following yesterday's incident."

Increased patrols and more police officers will be on the streets of Greater Manchester "as a reassurance measure", he said.

"I would also like to urge the people of Greater Manchester to remain vigilant, and if you do see anything suspicious then please report it."

A police cordon remains in place at Liverpool Women's Hospital following Sunday's explosion.

A spokesman for Liverpool Women's NHS Foundation Trust, which oversees the hospital, said it had restricted visiting access until further notice.

But it confirmed birth partners were permitted to attend for all appointments, including scans.

Families of babies on the neonatal unit have been asked to contact the unit to discuss access.

Once patients and visitors are onsite they will not be permitted to leave the building and come back, the trust added.

You can read more about the trust's latest guidance here., external

Recommendations for the UK's terrorism threat level are made independently from the government.

The current threat level is substantial - meaning an attack is likely, but there has been no change to this since the Liverpool blast.

The five levels of threat are:, external

• Low - an attack is highly unlikely
• Moderate - an attack is possible but not likely
• Substantial - an attack is likely
• Severe - an attack is highly likely
• Critical - an attack is highly likely in the near future

Image source, Getty Images

As we reported earlier, Prime Minister Boris Johnson is to chair a meeting of emergency committee Cobra to discuss Sunday's explosion in Liverpool.

Cobra meetings are called to help formulate the government's response to specific issues.

Ministers meet with civil servants, police, intelligence officers and other agencies to co-ordinate.

They take place in Cabinet Office Briefing Room A inside Whitehall, hence the name Cobra.

Downing Street may choose to reveal brief details of discussions, but matters are ordinarily considered secret.

Sharon Cullen and her family were evacuated from their home on Sutcliffe Street at about 21:45 GMT on Sunday.

It happened after three men - aged 21, 26 and 29 - were detained on Sutcliffe Street, Kensington shortly after the blast.

She said: "The police pounded on my door and an officer said 'we need to get you out of the house as soon as possible'.

"They said 'whatever is going on at the back of the house, it could blow the block'.

"It was really frightening."

Image source, PA Media

Media from across the UK gathered at Merseyside Police's headquarters to hear the latest from the investigation, Davinia Ramos reports.

During the press conference, officers looked concerned and saddened at the events that had unfolded outside the hospital.

It is very clear that detectives are still trying to establish a lot of information and were unable to go into huge detail about the specifics so far, including the identity of the person who was killed.

But they were keen to emphasise that they have dealt with incidents like this in the past and were confident of making progress.

People should resist speculating on social media, police added.

Prime Minister Boris Johnson will chair an emergency Cobra meeting this afternoon in response to the terrorist attack at Liverpool Women's Hospital, Downing Street has said.

Image source, CARL BESSANT

There's been a lot of development in the past few hours - so let's re-cap with some key points about what we know so far.

• The blast outside Liverpool Women's Hospital has been declared a terrorist incident
• One man was killed and a taxi was destroyed in the blast - with the driver needing hospital treatment
• Four men have been arrested under the Terrorism Act
• The taxi driver has been praised for his heroic actions which appear to have prevented a larger disaster
• Police believe they know the identity of the passenger who was killed but have not released further details at this stage

Read more here.

A cordon remains in place outside a terraced house in Sutcliffe Street in the Kensington area of Liverpool.

A grey Mondeo car parked adjacent is also taped off as uniformed officers continue to guard the front and side alley of the property.

A young man was put into the back of a police car outside the address shortly after 09:10 GMT on Monday.

Police confirmed a fourth man has been detained under the Terrorism Act.

Detectives investigating the explosion outside a hospital believe they know the identity of the passenger who was killed in the explosion.

Assistant Chief Constable Russ Jackson said the man brought a homemade bomb with him into a taxi and asked to be taken to Liverpool Women's Hospital.

But he added that he cannot confirm his identity at this time.

The moment the taxi exploded was caught on a security camera.

The footage shows the driver of the car exiting the vehicle seconds after the explosion happens.

It contains distressing scenes.

The journey to Liverpool Women's Hospital from a nearby street appeared to have been "unremarkable" before the blast broke out, police have said.

Speaking to journalists, Russ Jackson, of Counter Terrorism North West, said officers had yet to receive a full account of the incident from the driver of the taxi that exploded.

The driver, named locally as David Perry, is still shaken and injured, ACC Jackson said, but he has left hospital.

As we have been reporting, a series of raids have happened since Sunday's explosion.

The first happened near Rutland Avenue, where the passenger of the taxi involved was first picked up.

Around an hour later, another raid on Sutcliffe Street led to three people being detained.

We've heard in the past hour that a further arrest of another man has taken place nearby.

This is the taxi driver praised for his heroic actions following Sunday's blast at Liverpool Women's Hospital.

David Perry is said by police to have picked up a man in the Rutland Avenue area of Liverpool shortly before 11:00 GMT on Sunday.

The man asked to be taken to the Women's Hospital, a journey of around 10 minutes.

As the taxi arrived at the hospital's drop-off area, the car exploded. Mr Perry is believed to have escaped the car as it did so and while he sustained some injuries - he has now been released from hospital.

Earlier, he was praised for potentially preventing a much bigger disaster from happening.

In a statement read out during the news conference, Assistant Chief Constable Russ Jackson confirmed:

• An explosion outside the hospital has been declared a terror incident as investigations continue.
• Shortly before 11:00 GMT, a taxi driver picked up a fare in the Rutland Avenue area of the city and asked to be taken to the Liverpool Women's Hospital.
• As the taxi approached the drop-off point at the hospital, an explosion occurred from within the car.
• The taxi driver, who managed to escape from the vehicle, was treated in hospital for his injuries but he has since been released.
• Detectives are now treating the incident as “the ignition of an explosive device” and believe it had been manufactured and brought into the taxi by the passenger.
• A fourth man, aged 20, has now been arrested under the Terrorism Act.

Ending the news conference, Chief Constable Serena Kennedy also seeks to reassure the community and public.

She urges people to rely on official information about the incident directly from Merseyside Police, through its website and social media channels.

"The people of Liverpool are well known for supporting each other and at a time like this, it is needed more than ever," she says.

A fourth man has been arrested under the Terrorism Act, police confirm.

Counter Terrorism North West's Russ Jackson said: "A short while ago, again in the Kensington area, a further man aged 20 was arrested under S41 of the Terrorism Act."

Seeking to reassure the local community in Liverpool, ACC Jackson says investigators know the news will be of concern to them.

He adds it is a "reminder that the threat from terrorism remains significant".

"Police, with all our partners, will continue to work hard to protect the UK and keep the public safe, but countering terrorism also requires support from all corners of our society," he continued.