A Briton re-arrested over an alleged attempted murder in Portugal of which he was cleared 17 years ago says his world has been "turned upside down".
Photographer Graham Mitchell, 49, from Kent, faces a retrial following his arrest on a European Arrest Warrant.
Portugal's Supreme Court quashed his acquittal in 1996.
Mr Mitchell says he was not informed of the decision and was unaware of the bid to extradite him until he was arrested at his home by UK officers on 6 March.
An official at Portugal's Supreme Judicial Council said a fresh trial was also ordered in 1996.
Information on the documentation relating to the extradition request shows that a decision was made by the Portuguese authorities to apply for an arrest warrant in December 2008.
It was issued in November 2009 and was authorised by the Serious Organised Crime Agency - which handles extradition requests for the UK - last month.
Mr Mitchell says he was not on the run and was easy to trace - living at addresses in Surrey, Wales and now in Canterbury - over the last 17 years.
The former Scots guardsman, who lives with his wife and two children, said he was terrified at the prospect of returning to Portugal where he spent more than a year in prison awaiting trial in conditions he described as "hellish".
He said: "Our life's been turned upside down and inside out. Nothing's the same. Every waking moment is a constant worry.
"It's getting back to like when it was when I first came back from Portugal - it's hell on earth."
Mr Mitchell and his friend, Warren Tozer, were on a short break in Albufeira, in the Algarve, in May 1994 when they were arrested by Portuguese police investigating a serious assault on Andre Jorling, a 26-year-old German.
Mr Jorling had sustained severe injuries after falling off a 12ft-high sea wall. He was left paralysed from the waist down.
At their trial in March 1995, Mr Mitchell and Mr Tozer were cleared. They were given their passports back and allowed to return to the UK. A TV crew from BBC One's Panorama programme was covering the case at the time and filmed the court proceedings.
The footage shows the judge dismissing the case against the two Britons. They are shown smiling and embracing before leaving the courtroom.
Mr Mitchell, who was treated for post-traumatic stress disorder following his prison ordeal, said he had re-built his life and was the happiest he had ever been until the knock at his door from police earlier this month.
He said that in "hushed tones" police informed him that the Portuguese had requested his extradition for "first degree murder".
It is thought the phrase, used on some of the documents, may be a translation error because other paperwork refers to the attempted murder of Mr Jorling, who is still believed to be alive.
Mr Mitchell was held overnight in Wandsworth Prison, in south London, before being released on bail, which includes conditions requiring him to provide a £5,000 surety and report to police daily.
He has already appeared at Westminster Magistrates' Court and has another hearing on 28 March.
It is understood that there has been no further contact between the Portuguese authorities and Mr Tozer.
Alex Tinsley, a strategic case worker at theFair Trials International campaign group which is helping Mr Mitchell, said he was aware of previous cases in which suspects had been sent for trial even though such a move appeared to be unfair.
"We at Fair Trials International regularly deal with cases where judges feel that cases shouldn't go ahead to extradition but they feel powerless to stop it," he said.
"That is a systemic problem with the European Arrest Warrant - it just operates as a streamlined system with no possibility for judges to apply reasonable safeguards."
The case of football supporter Garry Mann illustrated the difficulties UK courts have encountered in blocking seemingly unreasonable extradition requests.
Mann was sent back to Portugal to serve a prison term in 2010, six years after being allowed to leave the country.
In 2009, Edmond Arapi, an Albanian man living in Staffordshire, was detained by British police at the request of the Italian authorities who had convicted him of murder in his absence.
Mr Arapi had a cast-iron alibi but it took a year before the Italians withdrew the extradition request, finally admitting that they had mixed up his identity with someone else.
It is not clear on what basis Portugal's Supreme Court decided to overturn Mr Mitchell's acquittal.
There is no indication of possible new evidence in the extradition paperwork and the authorities have given no indication so far that they have such evidence.
According to Fair Trials International, the arrest warrant is based on the same facts that were the subject of the 1995 trial.
Under the European Arrest Warrant scheme, domestic courts have few powers to test the evidence underpinning a request for extradition because courts are not obliged to consider the merits of the case.
That was one of the concerns that led Home Secretary Theresa May to commission a review of the system.
The review, led by Sir Scott Baker, a retired judge, set out proposals to ensure that suspects were not transferred between countries for relatively minor crimes.
But Sir Scott concluded that, overall, the scheme was operating "satisfactorily" and contained "formidable" safeguards against abuse.
He said there was nothing he had seen to suggest that European Arrest Warrants were being issued in cases where there was "insufficient evidence".
The Home Office said it would respond to the recommendations shortly.
A spokeswoman said: "The government is reviewing the UK's extradition arrangements to ensure they work efficiently and in the interests of justice.
"We will continue to press EU countries to consider proportionality when issuing European Arrest Warrants."