Leading article: Justice at last for Sam Hallam

In retrospect, it is always easy to see the faultlines when a miscarriage of justice has occurred. In the case of Sam Hallam, who was wrongly convicted of murder, they were particularly clear. The evidence that he was part of the murdering gang was manifestly unreliable; one witness changed her story several times, both to police and in court, and another admitted his testimony was hearsay. Meanwhile, the police failed to pursue all reasonable lines of inquiry, Mr Hallam's alibi was not properly checked out, and his mobile phone data was not used to establish his whereabouts. Furthermore, there was material not disclosed to the defence which could have helped prove his innocence.

It is some grudging testament to the British judicial system that it did eventually arrive at the truth. But questions must be asked about what took so long, when alarm bells were ringing so loudly – not least to Paul May, the man who fought to free the Birmingham Six and the Bridgewater Four, and who ran the campaign for Sam Hallam which was also backed by this newspaper. This was no hunch. As long ago as June 2009, eight new witnesses came forward stating that Mr Hallam was not involved in the crime. Their statements were submitted to the Criminal Case Review Commission four years ago. For a young man unfairly deprived of his liberty, the wheels of justice cannot acceptably grind so slowly, however fine the result.

There are questions, too, about the quality of Scotland Yard's investigation. Not only was the senior investigating officer expected to handle 14 other major inquiries at the same time. Poor management and staff shortages were also factors in so flawed an investigation.

The injustice was not to Mr Hallam alone. With one innocent man freed, and only one still in jail for a crime committed by a group, the family of the victim, Essayas Kassahun, are nowhere nearer finding the truth or seeing his killers brought to justice. And Mr Hallam's father, unable to cope with his son's incarceration, committed suicide 15 months ago. It is not enough that an innocent man is now free after seven years in jail. The only hope of amendment is to ensure no other victim of a miscarriage of justice suffers for so long.