Proposals for a central database of all mobile phone and internet traffic have been condemned as "Orwellian".
But the Lib Dems slammed the idea as "incompatible with a free country", while the Tories called on the government to justify its plans.
"Ministers claim the database will only be used in terrorist cases, but there is now a long list of cases, from the arrest of Walter Wolfgang for heckling at a Labour conference to the freezing of Icelandic assets, where anti-terrorism law has been used for purposes for which it was not intended."