By the end of the day, he would be a free man sitting on a train bound for Sydney after his conviction was sensationally thrown out by the NSW Court of Criminal Appeal.

Mr Leung is the first person in NSW legal history to stand trial, three times, over the same death since Louisa the "Botany Murderess" Collins - who was the last woman to be hanged in the state, in 1889.

"I'm in shock," said the former Sydney jeweller during an exclusive interview with The Sun-Herald, less than 24 hours after his release.

"No more trials, no more courts, I am happy. But also I feel much anger and disappointment with the system," he said. "I always maintained my innocence but three times they [the Crown] tried to fill in the gaps so they could convict me."

Mr Leung's seven-year "nightmare" centred on events that occurred on the morning of Easter Saturday in 2007, when witnesses found him cradling his lover's head at the bottom of the stairs in their Alexandria terrace. By the time paramedics arrived, Mr Guzzetti, 72, had stopped breathing. It had been almost an hour between a loud bang that a neighbour heard and Mr Leung's phone call for an ambulance. In that call, he said: "I had a fight with my friend ... now my friend is dead."

The case later came to hinge on a bloodstained juicer found on the floor beside the body which the Crown alleged Mr Leung had used to strike his lover. Crucial medical and scientific evidence, however, proved inconclusive, stating Mr Guzzeti's injuries were consistent with both a physical attack and a fall down stairs.

At his original trial in 2009, Mr Leung was acquitted of murder when a judge directed the jury to find him not guilty - on the basis that there was insufficient evidence.

But the Crown used NSW's controversial double jeopardy laws, introduced in 2006, to have the verdict quashed. Mr Leung then faced court on a manslaughter charge but in an unexpected twist, became the first person in Australian legal history to be twice acquitted by a judge's directed verdict.

Wiping tears from his face, he told Fairfax Media that day he was "finally free" to move on. However, the Crown had other ideas. In March 2012, the NSW Court of Criminal Appeal upheld a second appeal and ordered that Mr Leung once again be tried for manslaughter.

In November that same year, he became the first man in NSW history to stand trial three times over the same death. Recalling the moment the jury returned to the courtroom, he said: "Because it was the first time a jury was judging me, I believed justice would come. And when the foreman came out with the jury, he smiled at me, so I believed this was also a good sign. But then I heard the word 'guilty' and my mind...my mind just blacked out," he said.

As he was led away to prison, Mr Leung yelled "this is wrong". In March last year, he was sentenced to a minimum four-and-a-half-years' jail.

Mr Leung revealed that since being jailed two years ago, he had been shifted between Silverwater, Parklea, Cessnock, Bathurst and Muswellbrook prison facilities, encountering repeated "homophobic" violence and abuse along the way.

"I was attacked in a laundry at Parklea and had three ribs broken. In Cessnock, I was targeted and needed stitches above my left eye. I refused to argue ... I tried to avoid trouble. But always, I was bullied."

Mr Leung was days away from his second Christmas behind bars on Monday when unbeknown to him, his solicitor, Ben Archbold, took carriage of some remarkable news.

In a majority decision, Justice Elizabeth Fullerton and Justice Christine Adamson ruled the evidence before the court was insufficient to convict Mr Leung beyond reasonable doubt. Specifically, they could find no evidence that the juicer was used in any offence. Neither did the evidence "go so far as to exclude a fall".

Mr Leung was playing table tennis when the prison's manager approached with "urgent news".

"There was no warning. It came so suddenly that my mind, it struggled. I was so overwhelmed."

After scrambling to make the last train out of Muswellbrook at 7.30pm - so he did not have to spend a further night in prison, Mr Leung arrived at Sydney's Central Station at 12.30am on Tuesday, "dazed", jaded, but joyous. "I wandered streets, sat in bus stops...I just wanted to be by myself, feel freedom, smell the air...deal with emotions."

The following morning, Mr Leung was met by his solicitor Mr Archbold who fulfilled his client's only immediate wish -  a bowl of museli "with real nuts and honey".

Mr Archbold said: "It's been an extremely long road but very satisfying to have played a part in justice finally being served." Of the Crown's "relentless pursuit" of Mr Leung, he added: "How much pain and suffering should one man have to be put through?"

Mr Leung's next battle is to gain access to his own house which, since the conviction, has been the subject of both a caveat and confiscation proceedings by the DPP.

He said, finally, he could now grieve his dead partner - without the lingering accusation being his killer. "My life starts again but without the person I want to share it with," he said.

Six days on, Mr Guzzetti's Italian-based family has yet to be informed of the latest twist in the long-running legal saga. A Sydney-based family friend, who preferred not to be named, said: "How do I even begin to explain this?"