Leading article: Hatreds that need exposing

The street violence outside a new mosque in Harrow last week was the worst in a recent series of running battles provoked by right-wing groups. The immediate cause of the fighting, which has flared up in several British cities in recent weeks, has been aggressive demonstrations by groups called "Stop the Islamification of Europe" and "English Defence League". They have succeeded in goading young Muslim men and far left groups into responding and sometimes into attacking the police. Plainly, ignorance about Islam is an underlying factor, but the causes of this conflict are a little more complicated than that.

The English Defence League seems to have arisen in reaction to the demonstrations by Islamicist extremists against British soldiers parading in Luton, which suggests there is a two-way process at work. In an atmosphere of fearfulness, ideologists of hatred on both sides are using provocation to recruit supporters. On the anti-Muslim side, ideologists of racism seek to present Islam itself as a threat; while on the other, ideologists of jihadism seek to exploit the hostility suffered by many Muslims as a tool of radicalisation. This is obviously a dangerous and potentially mutually reinforcing mechanism.

Of course, the roots of this disorder go further back than Luton. The reasons soldiers were parading on the town's streets, and protesters were demonstrating against them, arose out of 9/11 – eight years ago last week – and the military engagements in Afghanistan and Iraq that followed.

That is why the violence on the streets of Birmingham and Harrow last week is a reflection of almost everything else that dominates the news headlines, day in and day out. Last week alone, we had the convictions in the plane bomb plot; further evidence of weakening public support for the war in Afghanistan; a police investigation of allegations of MI6 complicity in torture; and, as we report today, new concerns about Somalia as a base for British jihadists.

Yet it is not the news itself that provokes street violence, but the uses to which news stories are put by malign ideologies. On the anti-Islam side, the ideologists of the BNP exploit ignorance of Islam and the cultures of British Muslims. Against all the evidence of the relatively peaceful coexistence of Muslims, Christians and post-Christians for centuries, they seek to present Islam as an intrinsically violent religion. They try to tie fear of terrorism to age-old hostility to immigration. In this, they are often assisted by elements of the press – last week saw reports that Mohamed is the second most popular name for newborn boys in Britain if different spellings are added together (which overlooks variations of James, Jake and so on, as well as the centrality of the Prophet's name in Muslim culture).

On the Muslim side, the ideologists of al-Qa'ida exploit the desire of some young men to fight back against racism, and the sense of solidarity that some British Muslims feel with their co-religionists in Iraq, Afghanistan, Palestine, Chechnya, Somalia, Uighur or Kashmir. This newspaper disagreed strongly with US-British policy in Iraq, but it never accepted that the motive was to oppress Muslims. Nevertheless, the winding down of our presence in Iraq and – after the deeply flawed elections – in Afghanistan offers the chance to kill the "foreign policy" canard for good.

The answer, on both sides, is openness, information and clarity. This may sound like the soggy liberal belief that if only people understood each other better they will come together; but clarity can often be painful. There are many people, for example, who disagree with the BBC's decision to invite a BNP representative on to Question Time. This newspaper supports the idea, not because it will bring people together, but because it will expose those of malign intent. That means engaging with the BNP, not allowing it martyr status – but it also means engaging with jihadist extremists and not allowing woolly notions of multiculturalism to obscure the fundamental inhumanity of their beliefs.

Of course, we should put the recent clashes on our streets in perspective. A minority of young men will always need little excuse for fighting, and these disturbances are small compared with proper riots of earlier decades. Long, warm summer evenings are also a factor – a factor that the tilt of the earth's axis will soon take care of. But there is a danger that the attitudes on both sides can become self-sustaining and can be pushed towards violent extremism. They must not be allowed to do so.