Clive Goodman warned executives after he was jailed in 2007 that hacking had been “fully supported” by the tabloid’s editors, including Andy Coulson, who later became an adviser to David Cameron.

In the letter, released by MPs, Goodman claimed that Mr Coulson had banned discussion of the practice in news conferences. The reporter wrote that he had struck a deal to keep his job if he did not “implicate” other members of staff.

Senior figures from News International have repeatedly told MPs that phone hacking was restricted to a “single rogue reporter” and insisted that no one else at the company condoned the illegal practice.