Three police officers remained in hospital overnight after they were mauled by a dog thought to have been responsible for another attack on a passer-by last year.
The three who were kept in hospital overnight were in a stable condition. One constable is facing skin grafts on his body.
Scotland Yard admitted it failed to pick up on intelligence that the "pit bull-type" animal lived at the property in Albert Square in Newham before they stormed the address.
The dog was shot dead at the scene by a marksman from the Metropolitan Police's CO19 firearms unit and its owner, a man in his 20s, was arrested by bloodied officers for grievous bodily harm and kidnapping.
Officers were sent to investigate reports that a man had been bitten by a dog in April last year but no arrests were made.
Commander Stephen Watson, commander for north east London, said: "This allegation was not picked up in the intelligence assessment prior to today's operation, and this now forms part of my review of today's events."
Newham Council said it had launched an investigation last year after receiving a complaint that a dog had bitten a cyclist in the square in April.
Animal welfare officers visited the property on May 6, but there was no response and the matter was discussed with the police in June with no further action taken.
A neighbour described how one officer leapt on to the bonnet of a car to escape the crazed brown dog, as the raid quickly turned into a savage attack.
Dennis Clarke said: "The dog was holding on to his leg.
"He managed to get to the wall but the dog got over the wall and was trying to attack him again.
"He scrambled on to the car, stayed there for a minute. He got down when another officer was screaming and yelling."
Blood was clearly visible near the entrance.
Clarke said he had previously warned Newham Council that the pet was dangerous, after he reported it for attacking another dog.
The 72-year-old added: "That was a dangerous dog. I informed the council about it, which is why the fencing was put up.
"It has already attacked another dog. The owner never had it on a muzzle or a lead, but he did after the previous attack. He didn't take it out a lot.
"I think people shouldn't have those dogs. They should be completely banned."
The 9am swoop was part of Operation Big Wing, a major Scotland Yard purge on wanted suspects across the capital.
The 48-hour operation saw hundreds of officers carrying out searches for people wanted by police or who had failed to appear at court.
A total of 1,619 "visits" were made across London, the force said.
Watson added: "I think what our officers have confronted is the bravery that they very often display in protecting Londoners on a daily basis.
"One man is in custody, inquiries continue, but the person was arrested in line with the original purposes of the inquiries and subsequently with offences concerning the Dangerous Dogs Act."
Dog bite incidents in the UK have risen 79% in London and 43% nationally in recent years, according to figures obtained by the Kennel Club.Suggest a correction