The Met Police is considering doubling the number of officers trained to deal with riots, its acting head has said.
Mayor Boris Johnson backed decisions by Acting Commissioner Tim Godwin.
Tim Godwin said the number of police given specialist "level 2" public order training could rise to 6,000.
And he admitted the force made mistakes in the aftermath of the police shooting in Tottenham of a man whose death sparked last month's disturbances.
Mayor of London Boris Johnson defended police handling of the riots, saying the "crisis" caught everyone unawares.
Both men appeared before MPs on Tuesday to discuss the riots which spread across London.
Mr Godwin said with hindsight more officers would have been deployed on the streets after the shooting of Mark Duggan by police in Tottenham.
"The number of sites of disorder was something we hadn't experienced in the city before - and that did take us by surprise," he said.
He said with the benefit of hindsight he "wished he had had lots more police officers on duty on the Sunday and then into the Monday."
Mr Godwin defended the force's actions saying that decisions on tactics and numbers were taken on the basis of the best evidence available.
He said he wished he had more officers available by the third day of incidents - but nobody had foreseen "22 boroughs of serious disorder" driven by "copycat" criminality.
Regarding riot training, he said: "Looking ahead at what might come in the future, I think we're going to need to increase it."
He said that 43 of the force's officers had received commendations for their "extreme bravery" and 282 had been injured.
But Mr Godwin also rejected suggestions that his commanders had used the wrong tactics or were lacking specific tools, such as water cannon or baton rounds, also known as rubber bullets.
"We had a full range of tactics," he told MPs. "It was purely numbers [of officers] that was the inhibitor."
"Baton rounds were available but I think we would have been having a different conversation [if they had been used and people had been injured].
"I take pride in the fact that we filled up prison places instead of hospital beds, and I think that's the British way."
Mr Johnson declined to agree with the prime minister that police had got their tactics wrong.
The mayor said lessons could be learned with the benefit of hindsight - but disorder had been contained.
The mayor and the Met's acting chief echoed Justice Secretary Ken Clarke's views that the riots were the legacy of a broken penal system.
Mr Godwin told the committee: "I think this is a wake-up call for the criminal justice system.
"We have in London been seeking to speed up justice, make it more relevant, make it more relevant to communities, and that's something that we need to do.
"The amount of people who have previous convictions does pose questions for us."
UNIFORMED POLICE ON STREETS DURING LONDON RIOTS
* SAT 6 AUG: 3,000
* SUN 7 AUG: 3,000 (then upped to 4,200)
* MON 8 AUG: 6,000
* TUES 9 AUG: 16,000 (total on duty 24,300)
* Source: Met Police
Giving evidence to the Commons Home Affairs committee, Mr Johnson said that the Metropolitan Police and the city's authorities had been completely surprised by the scale of the disorder in August that spread from one incident in Tottenham to other boroughs.
"I think with 20/20 hindsight people may feel that it would have been wiser to upscale the police presence.
"But if you look overall at what the police did on [the first] night and on successive nights and what they are doing now … the riots were contained and there were remarkably few casualties"
During the emergency recall of Parliament last month, Prime Minister David Cameron told MPs that there had been far too few police on the streets and they had used the wrong tactics.
Asked by the committee if he agreed with the prime minister, Mr Johnson said: "It's self-evidence that there was a difficulty, a crisis, on the Sunday and Monday that caught everyone unawares."
Mr Johnson compared the scenes in London to those in Paris six years ago. He said that the police had to rely on emergency powers to restore order in the French capital - whereas the British approach had ended the disorder within a week.
The Metropolitan Police has told the committee in a letter that policing the disorder cost £74m and they now have 500 officers working on investigations.
The force also said that its commanders took the decisions to increase the number of officers deployed over the course of the disorder and later informed the home secretary and prime minister. The decision to increase numbers had been taken before police chiefs met ministers in an emergency Whitehall meeting.
The MPs were hearing from the Mayor and police chiefs as new figures emerged about people who took part in the rioting and looting.
The Metropolitan Police says that the proportion of rioters with links to gangs has dropped from almost a third to 19%, almost certainly because detectives had arrested known suspects before targeting others filmed on CCTV.
Figures indicate that eight out of 10 offenders were known to the police and 75% of them had a criminal record.
In an article published in the Guardian on Tuesday morning, Justice Secretary Ken Clarke blamed the "broken penal system" for the riots.
He said the Ministry of Justice's latest statistics showed that the hardcore of those involved had previous convictions and the criminal justice system had failed to stop them reoffending.