It was heart-warming to see the good folk of Clapham, Hackney and the rest mobilise themselves for a mass clear-up, using the same social media that had summoned the urban pillagers less than 24 hours before. Raising their brooms and dustpans aloft, they appeared the very model of David Cameron's Big Society. Whoever would have forecast that it would be looting mobs in London that would give it birth?
Yet the broom-wielders of Clapham have not been the only manifestation of the big society" spawned by this lawlessness. In north London, Turkish Kurds wielding pieces of hosepipe and baseball bats saw off would-be raiders and trashers. In Southall, to the west, it was Sikhs who turned out en masse to defend their threatened businesses. And in Eltham, to the south-east, none other than Millwall fans mounted the community defence, in the name of Eltham and England. Let down by the police, they all said in their different ways, they would not shrink from doing the job themselves.
Which might not be quite as reassuringly Big Society as it seems. We may believe that the line between laudable community spirit and dangerous vigilantism is distinct. But when the legitimate forces of law and order leave a vacuum, that line risks becoming perilously blurred.