Police looking on Facebook and Twitter for signs of unrest spreading will have missed out – they should have watched BBM

In October 1985, on the Broadwater Farm estate in Tottenham where the death of Cynthia Jarrett sparked riots that culminated in the brutal murder of PC Keith Blakelock, a community leader stood on his chair at a packed open-air meeting.

The man bellowed into a megaphone to the 150 residents in front of him: "You tell them that it's a life for a life from now on. This is war."

Over whoops and cheers from the residents, he turned to a huddle of police officers standing 50 yards away and warned: "I hope you're listening. There is no way I am going to condemn the actions of the youth on Sunday night."

Twenty six years later, police officers are still listening – but the megaphones and open-air meetings have been largely replaced. This weekend's north London riots, the Daily Mail announced on Monday, were "fuelled by social media".

But is this necessarily the case?

Certainly, the first online gathering of people mourning – and soon vowing to avenge – the death of Tottenham resident Mark Duggan took place on Facebook. Some of those behind the page, which now boasts more than 7,500 fans, launched into action shortly before 10.30pm on Saturday evening – more than five hours after the first public show of protest, outside the police station on Tottenham High Road.

At 10.45pm, when rioters set a double decker bus alight, the page posted: "Please upload any pictures or video's you may have from tonight in Tottenham. Share it with people to send the message out as to why this has blown into a riot."

However, otherwise, if there was any sign that a peaceful protest would escalate, it wasn't to be found on Facebook. Twitter was slightly more indicative: tweets about an attempt to target Sunday's Hackney Carnival were spotted by police and the event was abruptly cancelled.

Scotland Yard warned on Monday afternoon that those "inciting violence" on the 140-character social network would not go unpunished. Deputy assistant commissioner Stephen Kavanagh confirmed that officers were looking at the website as part of investigations into widespread looting and rioting.

However, the most powerful and up-to-the-minute rallying appears to have taken place on a more covert social network: BlackBerry Messenger (BBM).

Using BlackBerry handsets – the smartphone of choice for the majority (37%) of British teens, according to last week's Ofcom study – BBM allows users to send one-to-many messages to their network of contacts, who are connected by "BBM PINs". For many teens armed with a BlackBerry, BBM has replaced text messaging because it is free, instant and more part of a much larger community than regular SMS.

And unlike Twitter or Facebook, many BBM messages are untraceable by the authorities (which is why, in large part, BBM is so favoured by Emirati teens to spread illicit gossip about officialdom).

One BBM broadcast sent on Sunday, which has been shown to the Guardian by multiple sources, calls on "everyone from all sides of London" to vandalise shops on Oxford street.

It said: "Everyone from all sides of London meet up at the heart of London (central) OXFORD CIRCUS!!, Bare SHOPS are gonna get smashed up so come get some (free stuff!!!) fuck the feds we will send them back with OUR riot! >:O Dead the ends and colour war for now so if you see a brother... SALUT! if you see a fed... SHOOT!"

Another sent shortly before the outbreak of violence in Enfield on Sunday afternoon reads: "Everyone in edmonton enfield wood green everywhere in north link up at enfield town station at 4 o clock sharp!".

Jenny Jones, the former deputy mayor of London, blamed an under-resourced force for missing the tweets and the status updates. "It's quite possible if they had more resources they could have picked up on this," she said.

But maybe they were looking in the wrong place. Just as Tottenham residents in 1985 lambasted the media for scaremongering about protesters – the Daily Express suggested some had been trained in Russia – today's rioters might be surprised to read about "Twitter-organised chaos".

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