It is all too easy to forget, amid the euphoria of the Olympics, just how different the public mood was just one year ago. For five long days and nights last August, riots spread from London to Birmingham, Liverpool, Manchester, Salford, Nottingham, Bristol, Leeds and even to quiet towns like Gloucester. Five people died, 4,000 were arrested, and any number of shops, flats and businesses were destroyed. In all, one of the biggest outbreaks of civil unrest for generations wreaked more than £200m worth of damage.

Tomorrow is the first anniversary of the incident which sparked the rioting – the police shooting of a black man, a gangster whom they claimed (wrongly, it turned out) was exchanging fire with officers. It is, therefore, a salutary moment to consider whether unrest on such a scale might happen again.

Certainly the intervening 12 months have brought no satisfactory answers to the many questions surrounding the death of Mark Duggan which prompted his family to claim police were pursuing a "shoot first, ask questions later" policy and first brought protestors onto the streets. No officer has been charged with any offence arising out of the fatal incident. An inquiry by the Independent Police Complaints Commission is proceeding so slowly that the coroner conducting Mr Duggan's inquest has threatened to bring contempt of court proceedings against the watchdog. Even Scotland Yard has condemned the tardiness, while the Duggan family has called for the IPCC to be abolished for institutional bias. Public confidence in either the police, or their regulatory authorities, is hardly bolstered by such proceedings.

Meanwhile, gloomier commentators are predicting that last summer's riots could easily reoccur. An official Government inquiry blamed a range of factors for the unrest, citing everything from chronic shortages of jobs for young people, poor parenting and the justice system's failure to rehabilitate offenders, to consumer materialism and youthful hostility towards the police. With socio-economic conditions broadly unchanged, the doom-mongers warn, the tensions that exploded last summer are equally unresolved.

There is some evidence to support such a position. Extensive interviews with rioters conducted by researchers from the London School of Economics suggested a strong sense of unfairness as a major motivation. Many contrasted the unethical behaviour of economy-busting bankers and expenses-fiddling MPs with the hopelessness of their own lack of opportunities. Others attacked austerity measures which left the rich unscathed and hit the vulnerable hardest, with student tuition fees and the scrapping of the education maintenance allowance widely cited causes of resentment. But although such sentiments cannot be entirely discounted, they carry a whiff of after-the-fact justification for behaviour which smacked as much of greed and opportunism as of politics by another means.

The conditions that allowed them to flourish are unlikely to be replicated, not least because the police have learned vital lessons about how to nip unrest in the bud before it spreads, paying more attention to the use of social media and refining tactics for deploying officers on the streets. The severe sentences handed out to rioters will also act as a powerful deterrent. And then, of course, there is the change to the collective mood brought on by, first, the Jubilee and, now, the Olympics.

Fears of a repetition of the events of last summer seem unduly alarmist, then. But that is no excuse for the circumstances around the death of Mark Duggan to remain so unsatisfactorily explained. One year on, those are the questions that still demand answers.