"It looked for about 36 hours that it was going to be a consequence-free crime.
"The police were ready for a political riot or a riot with a particular cause but they were not ready to deal with people who just wanted to smash down shops and loot things inside."
Earlier Lord Coe, the chairman of the 2012 Olympic Games, said the capital had been transformed completely since riots broke out across the capital exactly a year ago, with foreign athletes and spectators alike receiving a warm welcome from British volunteers and crowds.
He said the world saw a "very different" London last August, when widespread violent disorder erupted after police shot 29-year-old Mark Duggan dead in Tottenham.
Lord Coe said he did not recognise the city of his birth in the riot-torn summer of 2011, but he added: "What I am seeing at the moment, and what they (overseas visitors) are seeing at the moment, is a London that I do recognise now.
"I think that that's for me been a very important journey over the last year."
Boris Johnson, the Mayor of London, agreed that the success of the Olympics had delivered a timely message about "effort and achievement" a year after the unrest in England's cities.
"What the riots revealed was, I'm afraid, a deep social problem which requires lots of different solutions. There was a culture of easy gratification and entitlement, and all the rest of it, that is part of the problem, and you have to deal with that," he told BBC Radio 4's Today programme.
Mr Johnson said sport and the Olympics have a role to play in tackling these problems, with sport building character, confidence, self esteem and the ability to understand how to lose.
Three-quarters of Britons believe that staging the Olympics in London has given the rest of the world an "overwhelmingly positive" image of the country, according to a survey conducted by the organisers of the Games.
Lord Coe agreed with the finding, saying: "We have seen it in the way that we have welcomed the world into our neighbourhoods.
"When they have got there and arrived in London and they have started their journey from the airport through to the competitive venue, I think they have been helped and they have been charmed."
The London 2012 chairman said foreign athletes have asked him to thank the British crowds in the Olympic venues for cheering them on as well as the home stars.
"Our athletes are performing, and our spectators are respectful, they are of course supportive, and they're not jingoistic," he said.
Lord Coe issued a "massive, massive thank you" to the people of Britain for getting so wholeheartedly behind the Games.
"Would I say I'm surprised? Probably not. But do I think it's probably one of the most extraordinary things in my lifetime I've seen? Then the answer is yes. People in their millions have joined in," he said.
He hailed the "extraordinary" gold rush for Team GB on Saturday as "the greatest single day in British sport".
"There is nothing that has ever matched that in terms of just sheer athletic performance, and the emotional roller that the whole nation went through that day," he said.
