The brutal murder of a serving soldier in Woolwich in broad daylight has shocked the country.
The prime minister has flown back early from France to lead the government's response to the suspected terrorist attack and security across London barracks has been stepped up.
But for the people who witnessed it, going about their daily lives in this corner of south east London, it will be a day they never forget.
At around 14:00 BST on Wednesday afternoon, witnesses reported seeing a car crash on Artillery Place, off John Wilson Street.
One eyewitness, who wishes to remain anonymous, told the BBC he had been walking his dog when he heard shouting about 50 yards away.'Animals'
"A man was running down the road and being chased by a car. The car then screeched to a halt and two men got out - one had some kind of sword.
"They literally swung at the other guy's head."
Graham Wilders told the BBC he was driving home and arrived on the scene to find a car crashed into a wall and a man on the ground.
"Two people were lying over him and I thought they were trying to resuscitate him," he said.
Mr Wilders said he drove on to park his car, and when he returned another witness told him the two men were stabbing the man on the ground. He said he saw one man carrying a gun.
Another anonymous witness said "two black guys" came out of the car together and "the white guy was in a white t-shirt with Help for Heroes on it", indicating the victim's link to the armed forces.
"They grabbed the guy towards the wall then stabbed him - stabbed him, stabbed him, cut his neck, and then dragged him into the middle of the road," he said.'Give comfort'
Speaking on LBC radio a man called James, who was at the scene, described the attackers as "animals".
"These two guys were crazy," he said. "They dragged the poor guy - he was obviously dead, there was no way a human could take what they did to him."
One of the surprising facts about the attack was that there were so many eyewitnesses, with the men making no attempt to flee and encouraging people to take pictures of them and their victim.
Another eyewitness, Joe Tallant, told the BBC the two attackers asked people on the street to call the police: "They wanted to get caught."
Lucky Awale, a local Muslim resident who has lived in the UK for 18 years, said she was "very, very scared" by what she saw.
She said one of the men was standing by the body talking as if he was "mad", adding that it was hard to make sense of what he was saying.
She said he claimed to have acted "in the name of Muslims", but she said this was "not right. It's not Muslim. We don't accept it."
The men were said to have been shouting Allahu Akbar (God is Great) as they carried out the attack.'In full control'
At the scene some people tried to help the victim. One witness saw a woman "trying to give him comfort", while other reports say a group of women formed a circle to shield the body from further attacks.
Mr Tallant said the attackers made it clear no men could come near the body, only women.
Cub scout leader Ingrid Loyau-Kennett, 48, used the time before the police arrived to talk to the attackers and try to draw their attention away from attacking anyone else, particularly children in the area.
Mulgrave Primary School, located very close to the incident, was "locked down" by head teacher David Dixon, after he saw the body lying in the street.
After her encounter with one of the assailants, Ms Loyau-Kennett told the Daily Telegraph: "He was not high, he was not on drugs, he was not an alcoholic or drunk, he was just distressed, upset. He was in full control of his decisions and ready to do everything he wanted to do."
The police armed response unit is reported to have take around 15 minutes to get to the scene, something some witnesses have criticised.'I was shaking'
When it arrived it "mounted the kerb", one witness said and "blocked the road off".
Another described how the attackers responded to the police presence.
She said: "We saw the black bloke come up with a gun so we've moved back and the black bloke had two - I don't know what they were - meat cleavers I call them and he ran towards the police response car so they shot him.
"Then the other one looked like he was going to lift the gun up so they shot him as well. I was shaking."
Julie Wilders, whose nine-year-old son attends Mulgrave Primary School, said the police had no choice but to shoot the man.
"They didn't even get the chance to get out of the car. He just ran to them so they shot him. They had to. It was either them or him," she said.
The two men were taken to hospital and are now under arrest.