The defendant, Roger Khan, was on trial for a vicious attack that left a man’s skull shattered and his brain exposed to the elements, but he had no lawyer representing him in court. He was dyslexic and had no legal knowledge, but the judge had told him that, if he fired the legal-aid lawyers he no longer trusted, he would have to defend himself. In fact, the only legal advice he was getting came from the prosecution. Throughout the four-week trial, a junior Crown barrister went down to the cells each morning to advise him on how to conduct his defence — although naturally enough, the prosecution’s aim was to get him convicted and sent to prison.

Even more strangely, some of those in court had been acquainted with each other long before the trial began. For example, one of the jurors knew the victim, the Newton Abbot restaurateur Nasim Ahmed, because she worked for his GP. (The juror was discharged at the end of the trial, but by then had been mixing with her peers for weeks.) She also knew other witnesses including Ahmed’s estranged business partner, Faruk Ali, who has a criminal record for violence and bigamy: according to one witness at the trial, in the weeks before the attack Ali had been threatening to ‘put a hit’ on Ahmed, although this is denied by Ali. Yet this trial did not take place in some backward dictatorship, but in England — before Judge Graham Cottle at Exeter Crown Court in July and August 2011. It ended when Khan, now 62, was convicted with his co-defendant, Faruk Ali’s brother Abul. Khan was sentenced to 30 years — an exceptionally harsh term for attempted murder. He remains in Whitemoor prison in Cambridgeshire.

There is no disputing the savagery of the crime. Ahmed and Ali owned two Indian restaurants, one in Teignmouth, the other in Newton Abbot. A little before midnight on 27 October 2010, Ahmed returned home from work. Two men emerged from the shadows and set upon him. The night’s takings, soaked in his blood, were left untouched.

This month, Khan’s case is being considered by the Criminal Cases Review Commission, the statutory body that investigates miscarriages of justice and has the power to order an appeal. (He tried to appeal two years ago but, once again, had no lawyers. A few days before the hearing, the London solicitor James Saunders agreed to act pro bono. Saunders had almost no time to prepare: the court turned Khan down.)

Acting for Khan now is Emily Bolton, the founder of a new legal charity, the Centre for Criminal Appeals. She previously founded and for four years ran Innocence Project New Orleans, which has freed no fewer than 26 innocent prisoners from the jails of America’s Deep South. ‘I’m stunned by the circumstances of Roger’s conviction,’ she says. ‘British lawyers used to come to volunteer on death-row cases in Louisiana and tell me, “This sort of injustice could never happen in the British system.” They were wrong.’

Cases like Khan’s may well become more common, for its ultimate cause was a lack of funds for his defence. The reason why the judge ordered him to defend himself is that he had complained in pre-trial hearings about his solicitors, claiming they were not doing enough to prove his innocence. The first time he did this, the judge allowed him to switch to a different firm. But the problem persisted. Specifically, Khan said, they would not take the time to obtain or examine the hundreds of hours of CCTV footage shot in Newton Abbot on the night of the attack. Somewhere there, he insisted, were the images that would prove his alibi — that while he had been in Newton Abbot, he had merely gone to the pub, and then, having missed the last train home to London, slept rough in a local park.

He wanted the court to appoint new lawyers who would get hold of the footage. But the judge refused, saying he could either stay with the lawyers he had or represent himself. ‘I had no faith in them,’ Khan told me in the bleak Whitemoor visiting room. ‘I felt I had no choice but to do the job myself.’

As cuts to criminal legal aid have deepened, defence lawyers’ resources have been constrained. ‘Twenty years ago, in the brief I’d get for a serious case, I’d be sent a thick dossier,’ says a leading criminal QC. ‘It would contain numerous witness interviews done by defence solicitors, and all kinds of other goodies — the fruits of hundreds of hours of work. Nowadays, I’ll get asked to defend a murder on the basis of an email with just the prosecution witness statements attached.’

As for Khan, he was eventually sent a package of 89 DVDs in his remand cell at Exeter prison a few weeks before the trial. Here it was at last: the CCTV footage. ‘The only place I could view them was in the prison educational department,’ he told me. ‘Unfortunately I was only allowed there for one or two hours a day. Some of the disks were password protected, so I couldn’t view them at all. Others seemed to have bits missing.’

Recent analysis of the DVDs by Bolton and her colleagues has found two sets of images of men near the area where the attack took place at relevant times, carrying what might be weapons. But they are muddy and indistinct. And these were only the municipal cameras — the disks in the pub cameras, which might have conclusively established Khan’s innocence, had long been overwritten. There is little chance of finding a clear image of him now.

Other evidence that might have proved Khan’s innocence is only now being properly investigated. There was no trace of his DNA on the metal pole used to smash Ahmed’s skull, but there was DNA from someone else who has never been identified. The same goes for a jacket worn by one of the attackers, stained with the victim’s blood.

Khan is not a poster boy — he is not, to adapt a phrase used by criminologists, an ‘ideal victim’ of a miscarriage of justice. He was convicted in 1987 for armed robbery, although he protested his innocence of this crime, too, and the investigative journalist Paul Foot was preparing an article on the case at the time of his death. But if someone was trying to ‘set him up’, Khan’s previous convictions made him more vulnerable, more plausible as a suspect, even though at the time of his arrest he had been straight for 15 years, working as a handyman and settled with a long-term partner.

Khan had never met Ahmed, nor his business partner Faruk. But his co-defendant Abul Ali, to whom he was related by marriage, lived near him in east London, and had asked him to share the driving on a trip to Devon. Unknown to Khan, Abul and his brother Faruk had accused Ahmed of sexually abusing another family member. According to witnesses at the trial, they were trying to extort thousands of pounds from him and force him to take a polygraph test.

Abul supported Khan’s alibi, saying that after they reached Newton Abbot, he gave him the money for his train fare home, and Khan got out of the car. He said that afterwards two white men got in. He gave them £200: their role, apparently, was to ‘persuade’ Ahmed to take the polygraph.

It would have been a challenging case for a skilled QC. Small wonder Khan struggled. At one point he exclaimed: ‘I am not really getting a fair trial, am I your honour? The odds seem to be packing up against me. One minute, one thing happens. The next minute, another thing happens. I have no idea what is happening there. Then something else happens. I am supposed to sit here, take it, and everything is fine with everyone else, but I am the one going, the lamb that is going to the slaughter.’

On the days he gave his own evidence, he was on hunger strike, and was faint from the lack of food. The judge observed his poor condition, but said: ‘I have already expressed my serious anxiety about this declining state of health, but I am not going to let this trial be held to ransom. We will get to the end of this case, one way or another.’

At Whitemoor, Khan described the meetings in the courtroom cells each day. ‘Every morning it was either the police or one of the prosecuting barristers who came to see me. They seemed to want to know what I was going ask the witnesses, and who I was going to call in my defence.’ Sometimes, he claimed, they persuaded him not to challenge their own witnesses’ veracity — warning that if he did, the jury would be told about his own previous convictions.

It has taken three years for Khan to reach the front of the long queue at the Criminal Cases Review Commission: with applications running at 1,500 a year, it has a gigantic backlog. If the commission does refer his case to the Court of Appeal, many more months will pass before it is heard.

‘The human cost of trying to do justice on the cheap is innocent people losing years of their lives in prison,’ Bolton says. ‘In this Magna Carta anniversary year, we need to recognise that this is the modern meaning of an overmighty state.’