Clare Short has lobbed another grenade into the government with her claim that British spooks routinely bugged UN officials.
By Nick Assinder
BBC News Online political correspondent
Ever since she quit the government over the Iraq war, she has maintained her fierce criticism of the prime minister for his role in taking the country into that conflict - even going so far as to demand his resignation.
Clare Short has regularly attacked Prime Minister
It is not the first time she has turned her anger onto her own party leader. She has resigned from the Labour Party frontbench three times - twice over the Gulf Wars and once over prevention of terrorism laws.
And along with former Foreign Secretary Robin Cook, she led the backbench critics of the war.
But unlike Mr Cook who quit on the eve of the war, the way she went severely damaged her standing with her previous supporters.
Rather than quitting before the war she publicly agonised over the rights and wrongs of the conflict - and only decided to quit her post as International Development Secretary once the main hostilities ended.
The MP has resigned before
That bemused many of her traditional allies in the Labour left - and her latest revelation is likely to raise the question of why, if she had been concerned by the intelligence services' behaviour, she did not resign at the time.
On the wane
Clare Short built her political career on her reputation as a principled straight talker and is a formidable figure in the Commons who can be emotional and occasionally savage.
Ms Short's passionate beliefs developed early in her life. She was born and bred in Birmingham, the second of seven children of Irish parents.
Her father, a teacher, came from Crossmaglen and she was once strident in her call for British troops to leave Northern Ireland.
With a degree in political science, Clare Short had no notion of entering Parliament until she worked as a private secretary to a Conservative Home Office minister, Mark Carlisle, and found many MPs decidedly "unimpressive" at their jobs.
She thought "I could do that" and in 1983 became the member for Birmingham, Ladywood.
An early target was The Sun's Page Three girl and similar newspaper photographs. The failure of her bill to ban them was inevitable.
After calling for the legalisation of cannabis and suggesting that perhaps people like herself could afford to pay more tax, she strained Tony Blair's patience when she refrained from backing his line in a TV interview about tube strikes.
Later she stunned Westminster by introducing her secret son, Toby, to the public, 31 years after she had given him up for adoption.
Her recent rebellions include stands over the sale of an expensive military air traffic system to Tanzania and government plans for top-up fees for students.
Ms Short was also the first cabinet minister to condemn Labour's acceptance of a donation from soft porn publisher Richard Desmond.