i only found out about this yesterday, in passim from another indy article, but with no details, and no real chance of getting ready for it.
you know what i suspect ? in fact i know it ... the british left 'en masse', particularly the Labourites, are not really too bothered about NATO, any more than they are concerned about 'free speech', as your other article goes into in some detail. Its quite clear that in 1999 there were two groups of protesters, one concerned with corporate capital, as at J18, and another anxious about NATO, but there was little crossover. British politics, or the feeble pastiche thereof, is limited to debate on domestic policy, but foreign policy tends to be sacrosanct. There was a huge NATO display in the Docklands last fall, but no protest whatsoever. Certain features of foreign policy may be challenged, but the basic notion that Brit does Good Abroad persists, somehow.
Nor indeed, was NATO opposed by the whole left last year. Some groups had extremely faulty reasoning, and I see no evidence that they've faced up to their blunders. I just hope that IMC sections are not torn by the same confusion; it would be a tragedy to see some coming out in favor of humanitarian cluster bombs. Even if not, there will have to be a debate if NATO resumes action in the Balkans, for there will be plenty of well meaning souls bleating as they did back then.