Oliver Letwin, a Cabinet office minister and considered a right hand man of Cameron, was caught dropping documents into trash cans in St James park on five occasions.
The throw aways included sensitive correspondence on terrorism, national security and his constituent' s private details, the Daily Mirror reported.
It said, the minister left in bins, for all to see documents dating from July 27, 2010 to September 30, 2011 and contained five intelligence and security committee letters.
Calling it a shocking security scandal, the tabloid claimed that it had witnessed 55-year-old Letwin dumping more than hundred papers in a security breach in St James Park.
Letwin is one of PM's closet advisers and has access to highest level of government. The paper said it first spotted Letwin publicly disposing off secret memos on Sept 7.
The minister and Cameron's Eton chum was not only caught dumping papers, but even handing papers to a rubbish collector. Letwin's office said papers were not "sensitive".