British businessman Shrien Dewani has been dramatically cleared of the murder of his honeymoon bride Anni.
Judge Jeanette Traverso dismissed the case against Dewani after roundly condemning the evidence of the chief prosecution witness.
Announcing her ruling, the judge said: "The accused is found not guilty of this charge."
Giving her ruling in Cape Town on an application by Dewani's defence lawyer Francois van Zyl to dismiss the prosecution, Judge Traverso said cab driver Zola Tongo's claims about the murder of Anni Dewani were "riddled with contradictions" and "highly debatable".
The judge said the evidence presented by the prosecution fell "far below" the required threshold.
She said the only reason not to grant the application would be in the hope that Dewani would implicate himself if he gave evidence.
But to do so would be a "manifest misdirection", she said.
Dewani, who was finally extradited this year to face trail accused of planning the murder of his wife in November 2010, listened intently as key evidence against him was criticised by the judge.
Three men have already been convicted of their role in the death, after the taxi the Dewanis were travelling in was hijacked as they passed through a township late at night.
Dewani has always denied any involvement in the plot. But prosecutors said bisexual Dewani wanted out of the relationship and plotted for his engineer wife, 28, to be killed in an apparent botched hijacking.
Dewani is expected to be granted permission to return to the UK as a free man.
Dewani has been held at the Valkenberg Hospital on the outskirts of Cape Town since he was extradited in April this year.
Dewani, from Westbury-on-Trym, denied murder, conspiracy to commit kidnapping, robbery with aggravating circumstances, kidnapping, and defeating the ends of justice.
Lawyers for Dewani last month applied for the judge to dismiss the case - although they have refused to confirm if Dewani would be free to return to the UK immediately.
Dewani has been discharged without ever giving evidence.
Last week the family of Mrs Dewani - previously known as Anni Hindocha - begged her accused widower to ''tell the world what happened the night she died''.
Tensions between the Hindochas and Dewani ratcheted up a notch at a press conference in South Africa, when her brother Anish implored Dewani to take to the witness stand and tell his story for the first time.
In a statement, Mr Hindocha said: ''It would be a terrible development in what has been a four-year wait if we and the people of South Africa are not afforded the full story.
''If they are not given the full facts, and by that I mean Shrien Dewani telling the court his version, then Anni's death will remain on the conscience of South Africa forever.''
The trial had been listed to last until the end of this week but delays triggered by legal wrangling, witness availability and sickness hit the case.
The latest delay, of almost two weeks, was prompted by the defence application to the judge.
The Hindochas, who have travelled from their home in Sweden to sit through each day's evidence since it began two months ago, had said they were confident the trial will continue.
Dewani was on trial for allegedly plotting with cab driver Zola Tongo, Mziwamadoda Qwabe and gunman Xolile Mngeni to kill Mrs Dewani while they were on their honeymoon in Cape Town in November 2010.
Dewani claimed the couple were hijacked as Tongo was driving them through Gugulethu in his minibus. He says he was released unharmed and his wife was driven away. She was found shot dead in the abandoned minibus in Khayelitsha the next morning.
Tongo is serving an 18-year jail term while Qwabe is part-way through a 25-year jail sentence. Mngeni was serving life for firing the shot that killed Mrs Dewani, but died in prison from a brain tumour on October 18.