Geoff Hoon was condemned as a liar, bully and hypocrite at the Hutton inquiry yesterday.
The Defence Secretary had denied there was a plot to name Dr David Kelly as a BBC mole.
But Jeremy Gompertz, the QC for the dead scientist's family, claimed former Downing Street spin doctor Alastair Campbell had proved Mr Hoon's denials were false.
"The hypocrisy of these denials has now been disclosed by some passages of Mr Campbell's diary," Mr Gompertz said. He accused Mr Hoon and No 10 of deliberately outing Dr Kelly as a BBC source.
They had used him as a pawn in their battle with the BBC over the corporation's claim that the Government dossier on Iraq's arms had been "sexed up".
Mr Campbell and Mr Hoon had also acted like "playground bullies" to try to nail BBC journalist Andrew Gilligan, the inquiry heard.
Mr Gompertz summed up on the final day of the six-week London hearing: "No wonder Dr Kelly felt betrayed. In his despair he seems to have taken his own life."