Lib Dem home affairs spokesman Chris Huhne said the figures "beggared belief".
"Many of these operations carried out by the police and security services are necessary, but the sheer numbers are daunting," he said.
"It cannot be a justified response to the problems we face in this country that the state is spying on half a million people a year.
"We have sleepwalked into a surveillance state, but without adequate safeguards. Having the Home Secretary in charge of authorisation is like asking the fox to guard the hen house.
"The government forgets that George Orwell's 1984 was a warning and not a blueprint."
Brexit is no miracle cure, but it gives us the tools we need to succeed - To explain the modern trade environment I would describe it as thus. Imagine you were a small business and you found that there were bureaucratic barrier...
3 days ago