An MP has called for BlackBerry's instant messaging service to be suspended after it was used to organise riots across the UK.
David Lammy, MP for Tottenham where London's worst riots for decades began over the weekend, has urged BlackBerry maker Research in Motion to suspend BlackBerry Messenger (BBM).
"This is one of the reasons why unsophisticated criminals are outfoxing an otherwise sophisticated police force," he said on Twitter.
"BBM is different as it is encrypted and police can't access it."
The riots, in which shops are being looted and cars and buildings set ablaze, have spread from London to Birmingham, Manchester, Wolverhampton and West Bromwich.
Politicians and police are blaming the violence on criminals and hooligans but some commentators and local residents say its roots lie in anger over economic hardship in cities where the prospects for many youths are dim.
Many of the rioters favour BlackBerry Messenger over Twitter and other social media because its messages are encrypted and private, but the service is widely used and messages can easily be sent to groups.
Research In Motion said: "As in all markets around the world where BlackBerry is available, we cooperate with local telecommunications operators, law enforcement and regulatory officials."
The company declined to say whether it was handing over chat logs or user details to police.
Research In Motion's Inside BlackBerry blog was hacked this week by a group going by the name of Teampoison, who have posted a warning to the company not to cooperate with police.
"You Will _NOT_ assist the UK Police because if u do innocent members of the public who were at the wrong place at the wrong time and owned a blackberry will get charged for no reason at all," the statement said.
"If you do assist the police by giving them chat logs, gps locations, customer information & access to peoples BlackBerryMessengers you will regret it, we have access to your database which includes your employees information; e.g - Addresses, Names, Phone Numbers etc. - now if u assist the police, we _WILL_ make this information public and pass it onto rioters," it said.
"One option would be to switch it off. But BBM is highly popular and has got a big installed base in the UK," said Geoff Blaber, analyst with UK telecoms research firm CCS Insight.
BlackBerry Messenger, or BBM as it is popularly known, has driven sales to new audiences for RIM in recent years as it expanded from its base as a tool for executives to a more consumer and younger clientele.
It has more than 45 million active users worldwide, 70 per cent of whom use it daily, sending billions of messages in total every month.
Users with data plans can instantly pass text messages, pictures and other files without incurring charges from their network carrier.
RIM has got into hot water in the past on the one hand for cooperating with governments seen as repressive, and on the other for not cooperating enough with the security needs of authorities in some countries.
Its encrypted services, which it moves over its own servers via telecom carriers, have been blamed for aiding militant attacks in India and for allowing unrelated men and women to communicate in Saudi Arabia and the United Arab Emirates.
In August last year, a source close to talks between RIM and Saudi authorities said the Canadian company had agreed to hand over information that would allow monitoring of BBM.
A deal was also reached in the UAE, averting a threatened ban on all BlackBerry services.
The company says it cooperates with authorities around the world with a consistent standard.
RIM has been relatively willing to provide authorities with access to its consumer services, such as BBM, but says it has no way of allowing monitoring of its enterprise email.
In the case of India, RIM gave the authorities access to BlackBerry Messenger services but said it did not have the technical capabilities to provide interception of corporate emails on the popular device.
India has demanded access to all BlackBerry services as part of efforts to fight militancy and security threats over the Internet and through telephone communications
In London, Deputy Assistant Commissioner Stephen Kavanagh of the Metropolitan police said: "Police have got extensive monitoring of this BlackBerry messaging model and actually a lot of people who are seeing these Blackberry messages are forwarding them to the police."
Police did not immediately respond to a request for more details of how they were monitoring message traffic.