I was returning home from the leafy London suburb of Sutton on Monday night when the mini cab driver turned around and asked: "You heard about the troubles in Tottenham?"
"Yes," I replied, "What do you make of it?"
"It's all these Blacks, isn't it. Bad news, isn't it." A lot of Londoners use the phrase 'isn't it' not as an interrogative, but as a declarative sentence.
This man was particularly concerned about the fact that the unprecedented rioting in Tottenham - a deprived north London neighbourhood - began with an incident in a private hire mini-cab.
On Thursday evening a 29-year-old father of four, who was a passenger in a mini-cab, was shot dead by police officers from a unit that deals with gun crime among Blacks. Police found a handgun.
Police say Mark Duggan was killed in an exchange of fire, but its version has been thrown into doubt after newspapers reported on Monday that the single bullet found lodged in the radio unit of one of the police officer at the scene was a police issue.
On Saturday evening around 100 people marched peacefully to the local police station demanding "justice" for Duggan's family. A community worker who was in the march said later police "resisted requests for a dialogue" for 48 hours, forcing marchers to remain on the streets until 9 pm.
Everyone knew - and police were warned - that some among the crowds could turn violent, and that's precisely what happened.
Parts of London have been burning for two successive nights, rioting and looting have spread in the north, and as far afield as Oxford Street in central London and Brixton in the south. There are security fears for this month's Notting Hill Carnival, an annual festival that sees a massive turnout of the capital's Black population.
Police and the Tottenham MP David Lammy blame the usual suspects: outsiders. This wasn't a race riot, said Lammy: "It was an attack on the whole of the Tottenham community, organised on Twitter."
Dhiren Basu, a former mayor of Haringay - the London borough that includes Tottenham - says that the underlying reasons are long-term deprivation and economic inequality.
"Tottenham is one of the poorest areas in London with high rates of Black unemployment," he says. "But in the same borough, we also have Highgate, where house prices can touch £38-40 mn. This is very unbalanced."
The Highgate People website reported "panic on the streets of North London," after looters attacked a video shop in the prosperous suburb of Crouch End on Sunday. "Police responded quickly to the attack, and no further offences have been reported," it said.