Excerpts from the tapes earlier leaked in the media had sparked a political storm with the conversations bringing out the nature of corporate lobbying and also its purported impact on politics. The income tax department placed transcripts of 5,800 tapped telephone conversations in 50 sealed envelopes.

The conversations were recorded as part of surveillance of Radia's phone on a complaint to Finance Minister on November 16, 2007 alleging that within a span of nine years she had built up a business empire worth Rs 300 crore.

The government had recorded 180 days of Radia's conversations--first from August 20, 2008 onwards for 60 days and then from October 19 for another 60 days. Later, on May 11, 2009, her phone was again put on surveillance for another 60 days following a fresh order given on May 8.