"I can't believe this happened here," one eyewitness told ITV News. Tap above to watch Antoine Allen's full report
A 26-year-old man has been arrested on suspicion of murder after allegedly running down a knife attacker who had stabbed a woman in the street.
The driver ran over a 41-year-old man in Maida Vale, west London at around 9am on Monday in an apparent bid to stop the attack.
Horror unfolded as the woman, aged 43, was stabbed several times in Chippenham Road in front of horrified onlookers.
Witnesses desperately tried to intervene to save her, but she was fatally injured by the attacker, who police said she knew.
Mulugeta Asseratte said: “It is a very terrible incident.
“I was coming up from the bakery to Chippenham Road and suddenly heard shouts of ‘stop it, stop it’ and it was a girl being attacked by a gentleman.
“I tried to look and even say ‘stop it’ and it would not.
“All of a sudden it moved to the street and no sooner than they reached the street than a driver came and hit both of them.
“We were all shocked and shouting and my heart goes out to the families of this fatal incident.
“This is something one sees in movies, not in real life.”
The Metropolitan Police said it had launched “an urgent investigation” after the horror unfolded in Chippenham Road at rush hour this morning.
Ambulance crews were called as well as London Fire Brigade, who freed the man as he was trapped under the vehicle, but both the woman and man died at the scene.
Detective Chief Inspector Neil Smithson said: “This morning an incredibly serious incident has unfolded in the Westminster area which has seen two people pronounced dead.
“Our officers are on scene and are working to establish exactly what has happened.
“As soon as we have more information will keep the public updated but for now we must avoid speculation and allow investigators to do their work.
“What I can say at this time is that the incident is contained and we do not believe there to be any wider threat to the community.
“We have spoken to a number of people already but anyone else who witnessed the incident, or who has information that could help us, is urged to make contact immediately.”
Raad Jiyad said he saw the attack unfold.
"This morning I woke up to drive my child to school and I heard some noise, someone saying, ‘Please help me, please help me’.
"I opened the door and saw a girl in the street on the floor and a guy with a knife, and I said ‘Please stop’, and another man came and tried to help.
"A car was driving normally along Chippenham Road and then it hit the man.
"We called the police and ambulance but it was too late. It was very bad, very shocking.
"It’s usually a very quiet area. I have two boys aged 10 and 16, and my 10-year-old saw it all from the window and he’s very scared now."
Labour MP for Westminster North Karen Buck tweeted: "Horrific events this morning in Elgin Avenue, which will be devastating for family and friends of those killed and also for the local community."
Tim Roca, local councillor for the Harrow Road ward added: "Just hearing about the tragic events on Chippenham road this morning."Absolutely awful news and fair to say the community is in shock."
Witnesses can call police on 101 quoting the reference 1496/24jan, or to remain anonymous contact Crimestoppers on 0800 555111 or online.