Where did they come from?

That was the question many spectators asked themselves this week as large groups of young people seemed to spontaneously melt out of the UK's streets and self-organise into violent mass riots across London and other cities.

Of course it didn't take long for technology - specifically the BlackBerry Messenger service that many of the rioters used to communicate - to take some of the blame.

Speaking in the House of Commons on Thursday Prime Minister David Cameron said that the government could propose new measures to shut down BlackBerry Messenger, and potentially other social networks, in the event of future riots.

So far at least Research In Motion (who make BlackBerry handsets) has said it will work with authorities. In a statement Patrick Spence, managing director, global sales and regional marketing said:

"We feel for those impacted by this weekend’s riots in London. We have engaged with the authorities to assist in any way we can.”

For most technology insiders, however, the notion that shutting down BBM could also shut down a riot is not only on ethically shaky ground, it also misses the point about how people communicate in the modern world.

"The idea that the rioters were using BBM is probably correct," said Stuart Miles, who is the founder of the UK's number one tech blog Pocket Lint. "But the idea that they latched onto it because it was a secure, untraceable 'weaponising of the mobile phone' as some people have called it is completely incorrect scare-mongering, and overblown."

The reason that BBM was used to help organise disorder on Monday is not that it was more secret or more secure than any other communication system.

It's just that it was cheaper.

"The fact is that the majority of kids of that demographic have BlackBerry devices because they're cheap and they have BBM, which allows them to text between each other and it doesn't cost anything. If you've got a phone that is out there amongst a majority of people that are in a movement, rioting, chances are they're going to use that."

And with Apple about to launch a similar service for not additional cost in the next few months, the idea of this being a RIM-specific problem is just going to become even less accurate.

"If you realised lots of kids were going around with baseball bats because baseball was a really popular sport in this country then would we be banning baseball?" he asks. "It's just too easy to turn around and say it's technology's fault, because technology is empowering people in ways that most politicians either do get or don't get."

Of course if RIM or the government did want to turn off BBM, it would technically be fairly simple to do so. BBM relies on the same infrastructure as other mobile phone services.

Whether it would be legal is another question.

For Mike Conradi, UK telecoms lead at global law firm DLA Piper, a change in the law would be needed to either shut down messaging networks or search those messages en masse. And that could have major consequences at home and abroad.

"I think that to shut down the BBM service certainly go on the wrong side of the boundary between freedom of speech and security," Conradi said. "The slightly less extreme option would be for law enforcement authorities to have a power to trawl through millions of messages looking for keywords that might indicate nefarious intent. That would also, in my view, be on the wrong side of the line and it would make it much harder for the UK when talking to authoritarian regimes in other countries to tell them they ought not to be doing similar things."

The law as it stands should be sufficient to catch perpetrators through BBM, Conradi adds. Information about a message, if not the message itself, can currently be disclosed to the police without breaching the Data Protection Act, he said. And if a message is deemed suspicious then the police can ask for a warrant to see the specific message. "That I think is a reasonably efficient process," Conradi said.

So how likely is it that the law will change?

"It's a lot more likely than it would have been, had it been suggested a week ago," Conradi said. "But I still would hope that common sense and reason would prevail and it will be defeated."

Reacting to David Cameron's proposal, Jim Killock, Executive Director of the Open Rights Group, said in a statement:

“Events like the recent riots are frequently used to attack civil liberties. Policing should be targeted at actual offenders, with the proper protection of the courts.

"How do people ‘know’ when someone is planning to riot? Who makes that judgement? The only realistic answer is the courts must judge. If court procedures are not used, then we will quickly see abuses by private companies and police."

And how has Research In Motion fared in all of this? Not well, it is probably fair to say. There is some evidence that the brand has taken a hit from its association with the riots, and certainly it must feel aggrieved that it has been singled out.

The media and political obsession with BBM is just their latest attempt to simplify the complex reality of modern tech says Jason Jenkins, editor of CNET UK.

"It's been strange, in a way slightly amusing to see how everyone jumps on this idea that there is a very easy, simple to explain cause to this whole thing when in fact it's very complicated," he said. "It's interesting to see newspapers pick on something other than Twitter or Facebook, which normally get the blame for this kind of thing. It's now BlackBerry's turn, I wonder who will get it next time?"

On the other hand, as much as RIM has been damaged by its association to the riots, there is still the possibility that no publicity is bad publicity.

"In a strange old way maybe this whole thing has done BlackBerry a little bit of a favour because at least people are talking about it in terms of having some kind of innovative technology," Jenkins said. "Up until now certainly the talk in the tech world has been how long does this company have left?"