3 dead, a fake bomb and heroic bystanders: Everything we know about the London Bridge attack.

— With AAP. 

Just before 2pm on Friday (local time) on London Bridge, Usman Khan wore a fake explosive vest and waved a long knife as he launched a terrorist attack on the public.

He stabbed several people, leaving two dead and three more injured.

Minutes after the stabbings, the knifeman was wrestled to the ground by members of the public. He was then shot dead by police.

One video posted on social media shows two men struggling, before police pulled a man in civilian clothes off a black-clad man on the ground. Gunshots followed.

Karen Bosch, who was on a bus crossing the bridge, said she saw police “wrestling with one tall, bearded man” and then heard “gunshots, two loud pops.”

She said the man “pulled his coat back which showed that he had some sort of vest underneath, whether it’s a stab vest, or some sort of explosive vest, the police then really quickly moved backwards, away.”

Armed-response officers then shot the knifeman dead.

Julia O’Dell, 25, who works in sales at a software store on nearby Borough High St told The Guardian she was on her lunch break shortly after 2 p.m. when people started running from London Bridge as the incident unfolded.

“You could see fear in people’s eyes; there were tourists as well as people who worked around the market,” she said.

Here’s everything else we know about the London Bridge terror attack 2019.

The London Bridge victims

Two victims died and three injured people were taken to hospital following the attack.

One of the victims has been named as 25-year-old Jack Merritt, a course co-ordinator for prisoners’ rehabilitation program Learning Together.

Shortly before the attack began, both Merritt and Khan reportedly attended a conference on prisoner rehabilitation at Fishmongers’ Hall in central London.

His father, David Merritt, shared to Twitter: "R.I.P Jack: you were a beautiful spirit who always took the side of the underdog."

He further noted that Jack "would not wish his death to be used as the pretext for more draconian sentences or for detaining people unnecessarily." The message has since been deleted.

Serena Wright, a lecturer in criminology at Royal Holloway University, wrote: "David, I knew your son through Learning Together and I loved him to pieces – he was the sweetest, most caring and selfless individual I’ve ever met. The warmest heart, always with time for anyone. Completely irreplaceable – I will mourn his loss greatly and honour his memory."

The identity of the second victim, a woman, who also lost her life in the stabbing rampage is not yet known.

As for those taken to hospital, health officials said one of the injured was in critical but stable condition, one was stable and the third had less serious injuries.

The London Bridge knifeman

The attacker has been identified as 28-year-old Usman Khan who was known to police and has previously been in jail for terror related offences. Police said Khan was convicted in 2012 of terrorism offences and released in December 2018 "on license", which means he had to meet certain conditions or face recall to prison.

Neil Basu, London's police counterterrorism head, said Usman Khan was attending a program at Cambridge University that works to educate prisoners when he launched the attack near London Bridge.

"Clearly, a key line of enquiry now is to establish how he came to carry out this attack," Basu said.

Several British media outlets reported that he was wearing an electronic ankle bracelet when he launched the attack.

Basu said the suspect appeared to be wearing a bomb vest but it turned out to be "a hoax explosive device".

Islamic State said the attack on Friday was carried out by one of its fighters and was in response to its calls to target countries that had been part of a coalition fighting the jihadist group, according to its Amaq news agency. The group did not provide any evidence for its assertion.

The London bridge bystanders

Images and videos show bystanders tackled the knifeman to the ground.

A video posted to Twitter shows a man in a suit and overcoat holding a long knife that he apparently had taken from the attacker. He has since been hailed a hero for his bravery.

This chap saved lives today. He wrestled a knife from the hands of the London Bridge terrorist.

Hero. #Londonbridgeattack pic.twitter.com/uczMrdaAY6

— Jonathan Turnock (@jw_turnock) November 29, 2019

The Mayor of London Sadiq Khan has praised the "breathtaking heroism of members of the public who literally ran towards danger not knowing what confronted him."

"They are the best of us," Khan said.

A man was filmed apparently trying to take a long bladed weapon away from the struggle on London Bridge.

Get live updates here: https://t.co/b0EsILlDU9 pic.twitter.com/AAhYHXlB2O

— Sky News (@SkyNews) November 29, 2019

It has since been revealed that a number of the men who were involved in tackling the terrorist down were also former offenders who were attending the criminology seminar.

The family of a woman who was murdered by one of the men being hailed a hero has expressed her outrage at the praise he is receiving.

"He is not a hero," the family member told The Sun. "He is a murderer out on day release, which us as a family didn't know anything about. He murdered a disabled girl. He is not a hero, absolutely not."

Political leaders expressed shock and sorrow at Friday's attack.

"We will not be cowed by those who threaten us," Labour Party leader Jeremy Corbyn said. "We must and we will stand together to reject hatred and division."

The UK's terror threat was last listed as "substantial" in August 2014; since then it has held steady at "severe," briefly rising to "critical" in May and September 2017.

The violence erupted less than two weeks before Britain holds a national election on December 12. The main political parties temporarily suspended campaigning in London as a mark of respect.

The violence erupted two-and-a-half years after a van and knife attack in the same area killed eight people.