Two police officers were stabbed by a knifeman today after they stopped him to check he had paid his bus fare.
The pair were attacked at a bus stop in New Broadway, a busy shopping street in the centre of Ealing, west London, at about 3pm.
A police constable suffered a slash wound to his throat and is in hospital in a serious but stable condition.
A police community support officer (PCSO) suffered stab wounds to his head as he wrestled with the attacker and is in hospital in a stable condition.
The attacker, aged in his thirties, was arrested at the scene and has been taken to a west London police station.
Eyewitnesses said the officers, who were wearing stab-proof vests, were part of an operation checking bus tickets.
One officer said the man pulled out a knife when it became clear he was about to be arrested.
Another eyewitness said the suspect knifeman had been travelling on a 207 bendy bus which travels between Hayes and White City.
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 incident occurred around 3.05pm. The Pc is believed to be in a serious condition. The PCSO is in a non-serious condition.
"A male has been arrested in connection with the incident."
The attack took place close to Christ Church School and a short distance from Ealing Town Hall in a street packed with shoppers.
Alfred Sayers said the attack took place on the opposite side of the street from his men's tailoring store.
He said: "I did not see the incident but I have heard it was very serious and the two policemen were stabbed.
"The first thing I knew was when police taped off the street, going right up outside my shop.
"We were moderately busy at that time and when I went outside there were ambulances and police vehicles everywhere."
A member of staff at Oxfam said the incident attracted "the quickest police response I've ever seen".
The woman said: "A customer came in and told us there had been an incident outside and within 30 seconds there were ambulances followed by police and a couple of policemen were running towards the scene."
Peter Smyth, chairman of the Met Police Federation, said the attack highlights the risked faced by officers and civilian staff every day.
He said: "It is sometimes the most minor things that turn out to be the most serious. Our thoughts are with them and their families and friends."
London Mayor Boris Johnson said he was "shocked", adding: "No place for this on the streets of London."
Model Portia Freno said she witnessed the attack as she travelled to a photoshoot.
Writing on Twitter, she said: "I am disgusted. Two police officers just got stabbed in the head in Ealing. Not a nice thing to witness at all."
Contacted directly, she declined to comment further.
Miss Freno posted a photograph showing an ambulance, a paramedic fast-response car and a large number of police vehicles parked in the street.
Transport for London said Ealing Broadway station, which operates District and Central Line services, had not been closed. Buses have been diverted.
London Ambulance Service refused to comment and referred all inquiries to police.
One witness described dramatic scenes of bloodied police officers running down the street while passers-by screamed.
Inam Mir, assistant manager of the Sony Centre on New Broadway, said police had been checking the tickets of passengers disembarking from a bus at a stop near the store when suddenly "it kicked off".
He said: "We heard screams and saw people running away. There were people running everywhere.
"We saw police officers who went to go and help running past with blood on their hands. Some were running past with medical kits.
"It's quite shocking. You don't expect to see that in broad daylight. There were police and ambulances. No-one really knew what was going on."
A crowd of people had already gathered at the bus stop before the incident took place this afternoon, he added.
"It was busy and some people were screaming, some were shocked and didn't know what to do," he said.
Expressing sympathy with the stabbed police officer and PCSO, he said: "They were only doing their job."
A heap of bloodied bandages and clothing and two policeman's hats could be seen lying on the pavement near the bus stop tonight.
The bus stop has been cordoned off with blue and white police tape, with three police cars parked in front of it.
A blue and white police forensic pop-up tent is now covering the scene of the attack and the road remains closed.
Paul McKeever, chairman of the Police Federation of England and Wales, said: "The thoughts of police officers throughout the United Kingdom are with our colleagues in Ealing, their families and their friends at this time.
"This appalling incident highlights the dangers that police officers face every day in the United Kingdom, all too often unseen and unheard."
One image taken by a bystander showed large pools of blood across two or three metres of pavement.
The poor quality mobile phone image showed clothing and a police radio scattered on the ground.
Four police officers could be seen crouching over someone on the ground, either the arrested man or a wounded officer.
The Met said both victims were based in Ealing Borough.
- More about:
- British Cycling Federation
- Foreign & Commonwealth Office
- London Ambulance Service