Former defence secretary Geoff Hoon is to stand down from Parliament at the election this year, it was announced today.
Mr Hoon, 56, has been MP for the Nottinghamshire seat of Ashfield since 1992.
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.
In his letter to Ashfield party members, Mr Hoon said it had been a "great privilege" to serve in Westminster and Brussels and he was "proud of what I have been able to achieve".
Without referring to specifics, he said: "Despite my involvement in difficult and sometimes controversial questions I have received consistent support from the people of Ashfield.
"They have recognised that it is necessary to take difficult decisions, that newspapers do not always report fairly or accurately and that I always tried to take decisions in the best interests of the country.
"I have had many Ashfield people say to me that they might not agree with my political views or my decisions but that they supported my right to be heard.
"I joined the Labour Party because I believed in equality, in freedom of speech and in tolerance, compassion and understanding for people, irrespective of their background and views.
"In whatever I decide to do in the future I will hold to those principles."