It comes as the Sun newspaper published a letter from Home Secretary Teresa May, where she says similar monitoring techniques helped put murderer Ian Huntley and the killers of Rhys Jones behind bars.
Meanwhile Labour Leader Ed Miliband says the government have not handled the policy in a sensitive and mature manner.
Yesterday it emerged that the data protection watchdog was demanding safeguards to protect privacy over government plans to increase monitoring of calls, emails and website visits.
Legislation due to be unveiled in next month’s Queen’s speech means internet companies would enable the government’s listening post at GCHQ to track communication through websites like Facebook and Gmail.
At the moment, if you send a message using email software like Microsoft Outlook, your internet service provider will store who it is from, who it is to, and the date and place it was sent. Likewise with phone calls and messages: your mobile phone network will store details.
If law enforcement officials want this information, they have to ask permission from the phone or internet company. But it is now reported they want to access this in real time and, perhaps, without asking permission. The proposal has caused uproar among civil liberties groups.
With emails sent through services like Gmail or Hotmail, and with phone calls made through services like Skype, it is unclear whether details can be kept by the phone or internet companies.