Leading article: The blue touchpaper is still being heaped up

It is a quarter of a century since the Brixton riots transformed a deprived section of south London into a conflict zone between the police and black youths. Looking back, it is tempting to regard those scenes of urban discontent as belonging to another, remote era. But the legacy of those three violent days in April 1981 is all around us.

The immediate result of the riots was that the police were opened up, for the first time, to reform. At the heart of the many grievances of Brixton's black community were the so-called "sus" laws. These enabled the police to stop and search anyone they suspected of planning a crime. The inevitable result was that many black people - especially young men - suffered daily discrimination and harassment.

The report into the riots by Lord Scarman was the first honest recognition by the British establishment that there was a problem with the police's attitude towards ethnic minorities. Lord Scarman recommended that racially prejudiced behaviour should be made a specific offence under the Police Discipline Code. His report also led to the creation of a Police Complaints Authority. Three years later, new stop and search rules were introduced, requiring the police to have "reasonable suspicion" of a crime. Lord Scarman's work prepared the way for the 1999 Macpherson report, which drew attention to "institutional racism" in the police. This resulted in another drastic decline in the use of stop and search.

The immediate causes of the Brixton riots were specific to the area. But high unemployment and deprivation on a national level contributed. The riots spread in that same year to Moss Side in Manchester and Toxteth in Liverpool. Today we are faced with different sorts of problems in our towns and cities. Asian, rather than black, communities seem more restive. The place names have changed. Bradford, Burnley and Oldham - not Nottingham, Notting Hill, and Brixton - are perceived as potential flashpoints. But there are strong similarities, too. The authorities are faced, once again, with an angry second generation. The parents of the Brixton rioters had come to help rebuild post-war Britain from the Caribbean in the late 1940s and 1950s. The Muslim parents of the rioters of northern England in the summer of 2001 came to Britain in the 1970s to work in the factories. Unemployment remains a major factor in urban discontent, too. In Brixton, around half of young black men at the time of the riots had no job. Today, unemployment among ethnic minority communities is still twice the general rate.

Most alarmingly, police stop and search has returned with a vengeance, thanks to recent anti-terrorism legislation. Black people are still six times more likely to be stopped than the general population; Asians are twice as likely. Under these laws, the police do not even require a "reasonable suspicion".

The task for our politicians has not changed in 25 years. Stamping out racism in the police force, encouraging employment and improving social conditions in the inner cities remain paramount. The Government's Social Exclusion Unit has identified the problem, but has so far had a disappointing impact.

In the summer of the 1981 riots, the response of the Tory government was to set up the Inner City Task Force. Today's Conservative Party, under David Cameron, finally appears keen to engage with the inner cities again. It would be churlish not to welcome this. But identifying the problem is just the beginning. The hard part is doing something about it. And in that sense, the questions posed by Brixton remained largely unanswered to this day.