Updated 1 July*

A US COURT has thrown out Bill Cosby’s sexual assault conviction and released him from prison, ruling that the prosecutor who brought the case was bound by his predecessor’s agreement not to charge the TV star.

The 83-year-old flashed the V-for-victory sign to a helicopter overhead as he walked into his suburban Philadelphia home after serving nearly three years of a three to 10-year sentence for drugging and violating Temple University sports administrator Andrea Constand in 2004.

In a statement, Constand and her lawyers called the ruling disappointing, and expressed fear that it could discourage sexual assault victims from coming forward. “We urge all victims to have their voices heard,” they added.

The former Cosby Show star was arrested in 2015, when a district attorney armed with newly unsealed evidence — the comic’s damaging deposition in a lawsuit brought by  Constand — brought charges against him days before the 12-year statute of limitations ran out.

But the Pennsylvania Supreme Court said district attorney Kevin Steele, who made the decision to arrest Cosby, was obliged to stand by his predecessor’s promise not to bring charges. There was no evidence that promise was ever put in writing.

Justice David Wecht, writing for a split court, said Cosby had relied on the former district attorney’s decision not to charge him when the comedian gave his potentially incriminating evidence in Constand’s civil case.

The court called Cosby’s arrest “an affront to fundamental fairness, particularly when it results in a criminal prosecution that was forgone for more than a decade”.

The justices said that overturning the conviction, and barring any further prosecution, “is the only remedy that comports with society’s reasonable expectations of its elected prosecutors and our criminal justice system”.

As Cosby was set free from the state prison in Montgomery County, his appeals lawyer, Jennifer Bonjean, said he “should never have been prosecuted for these offences”.

“District attorneys can’t change it up simply because of their political motivation,” she said, adding Cosby remains in excellent health, apart from being legally blind.

He later tweeted an old photo of himself with his fist raised and eyes closed, with the caption: “I have never changed my stance nor my story. I have always maintained my innocence. Thank you to all my fans, supporters and friends who stood by me through this ordeal. Special thanks to the Pennsylvania Supreme Court for upholding the rules of law.”

In a statement, Steele said Cosby went free “on a procedural issue that is irrelevant to the facts of the crime”.

He commended Constand for coming forward and added:

My hope is that this decision will not dampen the reporting of sexual assaults by victims. We still believe that no one is above the law — including those who are rich, famous and powerful.”

“FINALLY!!!! A terrible wrong is being righted — a miscarriage of justice is corrected!” the actor’s Cosby Show co-star Phylicia Rashad tweeted.

“I am furious to hear this news,” tweeted actor Amber Tamblyn, a founder of Time’s Up, an advocacy group for victims of sexual assault. “I personally know women who this man drugged and raped while unconscious. Shame on the court and this decision.”

Four judges formed the majority that ruled in Cosby’s favour, while three dissented in whole or in part.

Even though Cosby was charged only with the assault on Constand, the trial judge allowed five other accusers to give evidence that they were similarly victimised by Cosby in the 1980s. Prosecutors called them as witnesses to establish what they said was a pattern of criminal behaviour.

Cosby’s lawyers argued on appeal that the use of the five additional accusers was improper.

The Pennsylvania high court did not weigh in on the question, saying it was moot given its finding that Cosby should not have been prosecuted in the first place.

In May, Cosby was denied parole after refusing to participate in sex offender programmes behind bars. He has long said he would resist the treatment programmes and refuse to acknowledge wrongdoing even if it meant serving the full 10-year sentence.

Prosecutors said Cosby repeatedly used his fame and “family man” persona to manipulate young women, holding himself out as a mentor before betraying them.

In the deposition that spelled his downfall, the comedian said under oath that he used to offer tranquillisers to women he wanted to have sex with. He eventually settled with  Constand for 3.4 million dollars (£2.4 million).

*The initial version of this article was a breaking news post when the news first emerged from Pennsylvania at 6.15pm on 30 June but regrettably was not updated in the following hours. The piece was updated on 1 July to provide more context and reporting around the court’s decision.