Vince Cable has hit back over the newspaper sting which left him clinging to his Cabinet job, saying that it undermined the work of MPs.
The Business Secretary said The Daily Telegraph had done "great damage" by recording what he and other Liberal Democrat ministers thought were private conversations with constituents.
Mr Cable had to apologise and was stripped of his powers of regulating the media after his views about the workings of the Conservative-Lib Dem coalition and media tycoon Rupert Murdoch were made public.
In his first public comments since the story broke, he used an interview with his local paper, the Richmond and Twickenham Times, to express his anger at the way The Daily Telegraph obtained the story using undercover reporters posing as constituents.
"I feel quite angry and strongly about this. I've had constituency surgeries now for 13 years every week, that's well over 600," he said.
"Thousands and thousands of constituents have been to see me, often on very difficult and highly confidential issues which have been respected by me and by them.
"Then somebody who isn't a constituent falsifies their name and address and comes in with a hidden microphone - it completely undermines the whole basis on which you operate as a local MP. All my colleagues, of all parties, feel very strongly that some great damage has been done by this."
But a spokesman for the Telegraph Media Group said: "There is a clear public interest in The Daily Telegraph publishing this story. The Daily Telegraph takes the Press Complaints Commission code extremely seriously and has always adhered to it."
After The Daily Telegraph published details of another clutch of conversations in which Lib Dem ministers criticised Conservatives and the coalition, Lib Dem backbencher Adrian Sanders said the party leadership needs to "change direction".
"If lessons are not learnt from the higher education train crash, then the next four years are going to be very long indeed, with our prospects of advancement probably non-existent for a generation," he wrote on his blog. "The leadership, on the other hand, almost revels in having to take decisions against the grain of Liberal Democrat support and can't see the damage and hurt left in their wake."