A Scots businessman facing extradition to Taiwan following a fatal hit-and-run has launched a last ditch bid for freedom after more than two years behind bars at HMP Edinburgh.

Zain Dean fled the island in 2012 after he was found guilty of drunkenly crashing his car into a newspaper vendor’s scooter. Huang Jun-de, 31, died from head injuries and a court in Taipei sentenced Mr Dean to four years in prison for manslaughter.

Dean admits he was drinking on the night of the collision but insists he paid a nightclub employee to drive him home to the apartment he shared with his Taiwanese girlfriend, and CCTV footage which emerged after the trial shows the 44-year-old getting into the passenger side of his black Mercedes before he was driven away from the club.

Speaking exclusively to the Sunday Herald from prison where he has been held for more than two years while the courts decide whether he should be returned to Taiwan, Dean said: “If I was in Taiwan I’d have been given parole by now but I was not given that opportunity in Scotland.

“Every other prisoner is given the chance of parole when they reach a certain date. I’m the only one who hasn’t and I think it’s a bit unfair.”

Dean had settled in Taiwan and ran a successful business before the fateful night in March 2010 when his life changed forever. He said: “I was out with a client of my marketing company and we went to some Karaoke clubs.

“I was drinking so I decided to employ the services of a valet to drive us around. It’s very common to do that over there. Valet drivers work for these clubs to prevent drinking and driving. When I got in the passenger seat I fell asleep and I can’t even remember the collision.”

He was arrested the following day and police told the media they had CCTV footage which proved he was driving.

But during the trial the prosecution claimed every camera in the area was out of order and he was convicted on the basis of statements made by two workers from the club.

Dean said: “Before I’d given a statement, met with a lawyer or any investigation had been carried out I was presented by the police as guilty. I wasn’t even driving that night.”

He claims the officers who built the case against him are corrupt and alleges he wasn’t given a fair trial. The Taipei City Police Department was investigated in April 2010 after allegations were made by a local politician that nightclub owners handed over cash payments as part of a protection racket. A senior officer was sacked a month later and sanctions were taken against several subordinates.

However, at the time of Dean’s trial in 2011 there was public outrage at the death of Huang Jun-de and Dean was sentenced to two and half years, which was later increased to four years following an unsuccessful appeal.

Fearing that he’d be targeted in prison after the victim’s family allegedly put a price on his head, Dean, who was out on bail, borrowed a friend’s passport and fled Taiwan in August 2012. He claimed: “The family offered a cash reward for my life. It was all over the papers. I didn’t think I’d last a night in prison.”

Dean returned to Edinburgh and he and his Taiwanese girlfriend set up home in the New Town before launching a marketing business. But his life was thrown into turmoil again in October 2013 when he was arrested and imprisoned at HMP Edinburgh following an extradition request from Taiwan.

At a hearing in June 2014 Sheriff Kenneth Maciver ruled that Dean should be sent back to Taiwan to serve his sentence, a decision later rubber stamped by then justice minister Kenny MacAskill. Dean has appealed the decision and his fate is now in the hands of three appeal court judges who presided over a new evidentiary hearing last week.

They will determine whether the conditions of detention in Taiwan are compliant with the Article 3 of the European Convention on Human Rights, which prohibits inhuman or degrading treatment or punishment.

If the judges rule that conditions meet the required standards, Dean will be the first Briton to face extradition to Taiwan. The country recently went to the polls and elected a new government and the case has become a political football.

Taiwan has long sought international recognition after losing its seat at the United Nations to China in 1971. The People’s Republic regards the island as a rebel region that must be reunited with the mainland.

The previous Taiwanese president, Ma Ying-jeou, proclaimed that the Scot’s extradition will set an important precedent.

Speaking after Dean’s initial extradition hearing in June 2014, the politician said: “The government is very gratified at the ruling, which proves we are working in the right direction.”

The previous government pledged to give Dean a 6.9 square metre cell away from mainstream prisoners, who are typically put in 1.6 square metre cells.

However, Dean is concerned that the new administration won’t honour that commitment for fear of a public outcry.

He said: “Prisoners in Taiwan live in dreadful conditions. They’ve offered a special cell for me which is EU compliant.

“The new government have been voted in but they don’t actually take power until the end of May.

“It’s unlikely they will offer the same special treatment and the last thing they want is the public up in arms because a foreigner is getting better treatment.”

For now, Dean remains behind bars in Edinburgh with no prospect of bail.

A spokesman for the Scottish Courts Service said: “The hearing was before Lady Paton, Lord Drummond Young and Lady Clark of Calton who will issue their judgment in due course. There is no timescale.”

A Scottish Government spokeswoman said: “This extradition order is the subject of ongoing legal proceedings and we are therefore unable to comment.”

The Taipei Representative Office in the UK did not respond to a request for comment.