Ealing Broadway has been cordoned off after the attack Two police officers have been stabbed in Ealing, west London, while carrying out checks on bus tickets.
A Pc has been slashed in the neck and his injuries are said to be life-threatening. A PCSO was knifed in the arms and left seriously injured.
Police said they were stabbed in the Ealing Broadway area at about 1505 GMT.
It is thought they were attacked after it emerged one of the passengers was wanted for recall to prison. A 30-year-old man has been arrested.
“No place for this on the streets of London”
Boris Johnson Mayor of London
A BBC journalist who witnessed the incident said a large group of PCSOs and police were checking whether people had tickets at a bus stop.
She said several officers then jumped on a man and a police officer was left bleeding very heavily from his face and head.
It is understood the suspect was questioned during the stop and checks showed he was wanted for recall to jail.
A source said when the man realised there was about to be an arrest, he pulled out a knife and attacked the officers.
A man driving past the scene said: “I could see two policemen sprinting to the back of a police car to retrieve a green first aid kit.
“They rushed back to assist a policeman who had blood on him.
“I then noticed another policeman who was walking slowly and then collapsed on the pavement. His arm fell to his side.”
The eyewitness continued: “As I drove away I also noticed a number of policemen pinning a man to the ground. He was shouting.
“What disturbed me most of all was the amount of blood on the pavement, it was clear that someone was very seriously injured.”
A Metropolitan Police spokesman said the incident began when the officers stopped a member of the public. A knife was then drawn on the police and they were attacked.
The community support officer’s injuries are not thought to be life-threatening.
The area has been cordoned off and the victims have been taken to hospital by ambulance.
A Met spokesman said: “We can confirm that we have received reports of a police officer and a PCSO having been involved in an incident in the borough of Ealing and having sustained stab wounds.
“The Pc is believed to be in a serious condition. The PCSO is in a non-serious condition.”
Mayor of London Boris Johnson said on Twitter: “Shocked by the stabbing of a police officer and a PCSO in Ealing.
“No place for this on the streets of London.”
Councillor Julian Bell, leader of Ealing Council, described it as a “truly shocking incident”.
A BBC journalist who witnessed the aftermath, Ian Shoesmith, said: “The scene is sealed off behind a thin strip of blue and white as groups of policemen stand near to where the attack took place outside Specsavers and Jessops.
“On the wet pavement there is a clump of clothes, a police officer’s hat and what looks like blood soaked towels.
“Nearby a police information board reads, ‘Happy Christmas from Ealing Police’.”
London Ambulance have declined to comment.
Police vehicles and ambulances are blocking Ealing Broadway, which has been surrounded with police tape.
New Broadway has been closed in both directions, leading to queues in the surrounding area.
Several bus routes have been diverted but Ealing Broadway station, which serves the Central and District Tube lines and London Overground services, remains open.
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