Geoff Hoon MP to leave Parliament at next election
He faced anger from some activists after launching a failed coup attempt against Gordon Brown earlier this year with former Cabinet colleague Patricia Hewitt.
The putsch fizzled out after few Labour MPs rallied behind the pair's call for a secret vote on Mr Brown's leadership.
He was a minister throughout Tony Blair's time in power and led the Ministry of Defence during the Iraq War, later serving as transport secretary under Gordon Brown.
He quit the Government last June, saying he wanted to spend more time with his family. He later expressed an interest in being appointed the UK's EU commissioner, but did not receive backing from the Prime Minister.
A spokeswoman for Mr Hoon's constituency party said letters were being sent out to members today to inform them of his decision to stand down.