A cause for optimism amid the ruins of Brixton and Brick Lane

MAYBE IT is a lone nutter. Maybe the venues were random. Maybe all talk of murderous neo-Nazis is premature. But it doesn't look like it. After the Brick Lane bomb on Saturday evening it now looks a lot more likely, if not almost certain, that racism of an especially psychopathic kind is behind the bombing of Brixton and Brick Lane on two consecutive Saturdays. It now appears - years after the end of a long Cold War period in which it was widely, and sometimes exaggeratedly, assumed that the principal domestic threat to peace and order came from the extreme left - that the "enemy within" is one on the extreme, fascist, right.

How anybody would be prepared to "claim" a terrorist action like this, whether they had committed it or not, beggars belief. But all the signs are that the one of the most vicious of these Nazi groups, Combat 18, which has claimed responsibility for the Brixton bombing does not have the competence to have carried it out. Indeed, Combat 18 has been carefully monitored by both the police and the intelligence services since well before the general election and it was never thought likely to perpetrate anything like this.

Instead, tentative attention was turning yesterday to a what may be less a "group" than a small cell called White Wolves. Even to write that may be to do just what these people want - to give them, what is perversely for them, glory. But last week a number of black and Jewish parliamentarians (including Oona King, the MP for Bethnal Green, which includes Brick Lane) were sent letters threatening the "extermination" of black people and Jews - by "blood not by religion" - who had not left the country by the end of 1999. Moreover, the organisation, if that's what it is, is thought to have distributed advice on how to make a nail bomb.

Of course some of the victims at Brixton were white. And of course there might have been white victims, though there weren't, as well as Britons of Bangladeshi extraction in Brick Lane. But when someone as intelligent and level-headed as Ms King says that the homicidal attack in Brick Lane on Saturday night was "symptomatic of the backlash against the Lawrence inquiry", it is time to sit up and listen.

We won't know for some time whether the perpetrators of this act of terrorism - which is what it is - are mad as well as evil. But it is possible that they are an offshoot of one of those dedicated white supremacist organisations like Combat 18, who in turn stem at least indirectly from groups such as the British National Party which once had an elected representative in a ward not so far from the scene of Saturday night's car bomb. And if this sounds like guilt by association, that's just what it is. Nobody who makes racism his or her political raison d'etre can fail to take at least some responsibility for the influence of its poisonous propaganda on those willing to kill and maim for the same goals.

But the point about the backlash against the Lawrence enquiry, is, paradoxically, not a wholly discouraging one, for all the fear that must now be felt in ethnic minority communities outside as well as inside London. To the extent that Lord Macpherson's report on the hapless investigation into Stephen Lawrence's murder was a real watershed, it is a defeat for racism. And to the degree that racism is defeated in the larger society, the remaining racists may resort to desperate measures.

Maybe this is fanciful. Maybe these are simply sick and alienated people who just want to inflict the maximum pain on the maximum number, and would do under any circumstances. It certainly looks, as the Commission for Racial Equality's Claude Moraes suggested yesterday, that the Internet has become a market place for introverted and freakishly dangerous people to send each other information on how to make bombs, and that the kind of civil liberty which allows them to do so is no kind of civil liberty at all. Mr Moraes was surely right to suggest that the Government will have to review the regulation of the transmission of this kind of information - not to mention what he called "hate speech" - on the Internet.

But the most optimistic view is that these are people who fear, for the first time, that they are never again going to get what they want by mere persuasion or because institutions like the police are themselves, however implicitly, racist. Perhaps it is naive to say this. But it seems doubtful that Oswald Mosley's blackshirts or even a latter-day equivalent of Enoch Powell's dockers could get the same kind of support for a march through the East End today. More people understand today than would have done then that these are cowardly attacks - not only on one ethnic minority or another, but on what we should be proud to call inner-city Britain.

This isn't for a moment to ignore the fact that individual racist attacks aren't all too regular, or that in football grounds - for example - racist groups are not finding all too fertile territory for recruiting young men into racial abuse and violence, or that there isn't very real racial tension on some of our inner-city streets. Nor, moreover, does it mean that the aftermath of Brick Lane and Brixton is not a test of supreme importance, not least for the police.

Insofar as it was about racism, as well as about a breathtaking level of operational incompetence, the Lawrence report was not, for all that it was depicted otherwise, about racism in general, so much as about racism within the police, which assumed, as recently as 1993, that the murder of a black man was less important than a white one and - fatally to the police investigation into Stephen Lawrence's murder - that a black witness was less reliable than a white one.

A great deal has happened since then; those such as Ms King who have been in continuous touch with Scotland Yard since Saturday evening have been impressed by the speed and thoroughness with which, so far, the police have acted. What has been equally striking is the admirable restraint and calm of most community spokespeople in Brixton as well as in the East End.

As long as those who have most to fear from homicidal racist terrorists in their midst have confidence in the police's determination to hunt the perpetrators down, there is little danger of the vigilanteism to which, even 10 years ago, those communities would have been all too understandably tempted to turn. So far at least, that confidence appears to be justified. Which is as well. These people are not necessarily going to be easy to catch, or to prevent from striking again. But it should not be for want of trying.

This is the police's big chance to start expunging the stain left by the Stephen Lawrence enquiry. If they take it, grim as the circumstances are, it will be another landmark in Britain's process of growing up into a truly multi-ethnic society.