Facebook, Twitter and BlackBerry executives were meeting UK Home Secretary Theresa May Thursday to discuss whether their users should be blocked when they are plotting violence and criminality, it was announced. The likes of BlackBerry Messenger - a service which allows users to send free-of-charge real-time messages - was said to have enabled looters and yobs to organise their movements during the recent riots, leaving no paper trail, officials said. Troublemakers also harnessed the power of the social networking websites to incite unprecedented levels of civil disobedience. As politicians and experts debate the possibility of a clampdown on the technology in the future, Theresa May was holding talks with representatives from the social media industry to gauge how far the authorities could go with this. A Home Office source said there was \"no suggestion\" that any of the sites would be closed down. A Home Office spokeswoman said \"The Home Secretary will meet the Association of Chief Police Officers, the police and representatives from the social media industry. \"These discussions will help us determine how law enforcement and the networks can work better together. Among the issues to be discussed is whether and how we should be able to stop people communicating via these websites and services when we know they are plotting violence, disorder and criminality. \"Social networking is not a cause of the recent disturbances but a means of enabling criminals to communicate. \"We are working with the police to see what action can be taken to prevent access to those services by customers identified as perpetrators of disorder or other criminal action.\" Facebook pointed out that it already prioritised its review of content on the site that is \"egregious during sensitive times like the UK riots\", with a view to further reducing the time it took to take such material down and \"disincentivise bad actors on the site\". A spokeswoman said \"We look forward to meeting with the Home Secretary to explain the measures we have been taking to ensure that Facebook is a safe and positive platform for people in the UK at this challenging time. \"In recent days we have ensured any credible threats of violence are removed from Facebook and we have been pleased to see the very positive uses millions of people have been making of our service to let friends and family know they are safe and to strengthen their communities.\" Delegates from Facebook, Twitter and BlackBerry maker RIM will be joined by Lynne Owens, assistant commissioner of central operations at the Metropolitan Police, and civil servants from the Foreign Office and Department for Culture, Media and Sport. Mrs May will lead the private meeting along with security minister James Brokenshire and a member of the National Security Council. Prime Minister David Cameron told MPs after the riots that the Government was speaking to the industry and police to establish how to stop the internet being a tool for troublemakers to organise disruption. Asked about Twitter\'s role during the escalating violence in London, Met Police Acting Commissioner Tim Godwin told the home affairs select committee last week he had contemplated seeking the authority to switch it off. But he added \"The legality of that is very questionable and additionally it is also a very useful intelligence asset.\" Requesting that the micro-blogging site be turned off was \"something we are pursuing as part of our investigative strategy\", he said. Speaking after the riots, Mrs May said \"I will convene a meeting with Acpo (the Association of Chief Police Officers), the police and representatives from the social media industries to work out how we can improve the technological and related legal capability of the police\".