Lawyers for jailed Liverpool football fan Michael Shields have begun a challenge to try to overturn his conviction by a Bulgarian court. Two High Court judges in London are considering whether justice secretary Jack Straw is empowered to exercise the ancient "royal prerogative of mercy", even though Shields was convicted abroad.

Straw has previously maintained that the matter is out of his hands, saying that he has no jurisdiction to consider either a pardon or an early release. He has always insisted that the issue of a potential pardon was down to Bulgarian authorities. Yet Bulgarian Justice Minister Miglena Tacheva had sent a letter to Straw earlier this year, in response to a BBC documentary on the subject, saying that Shield's fate now lay in British hands. Tacheva stated that there would be no more legal procedures against Shields in Bulgaria, and that the UK could, therefore, release him.

Shields (22) is serving a 10-year sentence in the UK for the alleged attempted murder of barman Martin Georgiev in the Black Sea city of Varna, a few nights after Liverpool's victory in the Champions League final in Istanbul in May 2005. His conviction has been described by Fair Trials Abroad as a blatant miscarriage of justice. Shields has also had the consistent backing of his local Labour MP, Louise Ellman.

The eagerly awaited High Court judgement follows a surge of media interest in Shields' case. Shields' mother, Marie, recently travelled to Downing Street in London to discuss her son's case with Sarah Brown, wife of prime minister Gordon Brown. And, even more prominently, the Liverpool team displayed "Free Michael Shields" T-shirts before last week's match with West Ham at Anfield. Liverpool fans also held aloft a mosaic bearing the same message. The club's actions prompted the Football Association (FA) to consider instigating disciplinary measures.

Media and celebrities in Liverpool have also thrown their weight behind the campaign to free Shields. Local newspaper Liverpool Echo (no relation to The Sofia Echo) has been particularly vocal in the campaign but so, too, have celebrities such as actress Sue Johnston, star of the TV series The Royle Family.

The Liverpool team's ensemble display of support is reminiscent of high profile justice campaigns of the past such as the Birmingham Six and the Guildford Four, both involving people wrongly accused of perpetrating IRA bombings. Those with even longer memories may also remember the case of George Davis. On August 19 1975, while Davis was serving a 20-year prison sentence for armed robbery, the pitch at the Headingley cricket ground was dug up by his supporters, preventing further play between England and Australia.

Confession or red herring?
Varna Regional Court originally convicted Shields on July 26 2005. Shields has maintained his innocence amid a separate confession from another Liverpool fan, Graham Sankey, that he himself hit Georgiev with a 3.5kg stone slab over the head, sending him into a coma on May 30 in the Zlatni Pyasutsi (Golden Sands) resort.

According to the prosecution and eyewitnesses, Georgiev tried to stop a brawl among drunken Liverpool fans outside a bar in the resort. It was then that Shields hit him with the slab, leaving him on the pavement with a smashed skull.

Sankey had no connection to Shields or his family but had been arrested for violent offences on a number of occasions in the past. The court refused to acknowledge Sankey's confession unless he returned to Bulgaria or agreed to appear in a British courtroom for questioning, via video connection, by a Bulgarian court. Sankey was not prepared to do this and subsequently retracted his admission of guilt.

His original confession ran as follows: "Unfortunately, I had far too much to drink; I had been drinking lager for the better part of the day. In the evening I estimate that I drank nearly a full bottle of vodka and I was very, very drunk. I left the PR Club and I was making my way to my hotel. I remember seeing a disturbance and a fight was taking place involving a large number of people, some of whom were wearing red shirts. I could see bottles being thrown and as I drew closer a bottle smashed on the wall behind my head. As I turned to see where the bottle had come from I saw three men running at me with bottles and bricks in their hands. I panicked and stupidly picked up a brick and threw it in the direction of the men running towards me. I saw the brick hit one of them. I panicked and I turned and ran away and returned to the hotel."

UK media comment
The British media, particularly in the light of Liverpool football club's collective show of support, has been commenting more frequently on Shields' case. Reflecting on the wider campaign to free Shields, The Guardian's Lawrence Donegan said that those behind the campaign had succeeded in highlighting his imprisonment to the extent that it was now being deliberated before the High Court.

Donegan also said that the FA was right not to take steps against Liverpool football club for its show of support. "What Liverpool [football club] did was hardly the juvenile conduct for which the [FA's disciplinary] rules were designed, it was the last and logical step in what has been a sincere, responsible effort by the club to raise the profile of a subject which has generated significant public interest," he wrote.

The Daily Mail, in its opinion section, had a different take on the matter. "If Shields has been unjustly imprisoned, let the door fly open. But it's incumbent on us to recognise also that a Liverpool supporter maimed an innocent bystander, and that the biggest victim in all this is Martin Georgiev. Maybe Liverpool could make a gesture to him equal to their support for Michael Shields."