Amir is a simple lad but he's not that naive

Shortly before 11am yesterday morning Mohammad Amir, wearing a dark jacket and jeans and with his long dark hair hiding much of his face, picked up a casual shoulder bag, swung it into place and followed Salman Butt, Mohammad Asif and Mazhar Majeed out of the dock here and down the stairs to the holding cells.

There they separated. Butt, Asif and Majeed went to prison; Amir, after a brief return to court for a hearing about an appeal, was taken to Feltham Young Offenders Institute on the outskirts of London. He spent last night in the Bittern unit – each of the eight units is named after a bird – before being assigned a room as one of nearly 800 inmates aged between 15 and 21 for the three months he is expected to serve.

There has always been a separation between the four conspirators – Amir is seven years younger than Butt – and it was one recognised by the judge, the prosecution, who called him the "sacrificial goat", and the ICC, cricket's governing body, in determining what part the now 19-year-old played in the events at Lord's last year and how he should be punished.

Amir has never spoken publicly about what happened. At both the ICC hearing in Doha in February that saw him banned for five years and Wednesday's hearing in Court 4 here – the first time Amir appeared in the dock – it was left to his defence team to speak for him. The judge, Mr Justice Cooke, invited Amir to take to the witness stand after stating he did not accept the basis of the player's guilty plea; that Lord's was the only time he had been involved in corrupt activity. Amir declined, as is his legal right.

The fact that he was handed the lightest sentence was in part down to his guilty plea, his five-year ban by the ICC, his youth and the suggestion that he was influenced by others – the judge believes Butt in particular, and although Amir has said that none of the other defendants pressured him it is difficult not to regard the captain's corrupting authority as telling. Amir has also suggested he and his family have been the subjects of threats in Pakistan over him giving evidence.

But he is a guilty man who altered his story before finally admitting his guilt on 16 September – and it was clearly not a one-off offence as evidence produced during the trial of Butt and Asif demonstrated. Amir did what was asked of him at Lord's, and so in the middle of a devastating spell of fast bowling that glowingly displayed his huge ability his best time became his worst time.

Amir cannot be seen on a cricket field again until 2016 and whether he will ever be seen in the Pakistan shirt he professes to love is open to serious doubt. Will Pakistan's cricket authorities, desperate to clear up their game, want such a tainted figure back? He will only be 24 but five years out of the game will leave him as a 24-year-old fast bowler with the experience of an 18-year-old one. It is not an easy thread to pick up no matter the raw talent.

Amir is the archetypal street cricketer, born with the ability to bowl left-arm and fast, a combination capable of unsettling any batsman in the world. From a poor family, he left home aged 13 to begin being fast-tracked through the youth ranks of Pakistan cricket. Geoff Lawson, the former Pakistan coach, first met Amir as a 16-year-old. He tells how the boy from a small village near the Swat valley was once three hours late for an under-19 training camp because the Taliban had cut off the road.

Amir's rise was meteoric and brought a Test debut a year before the events at Lord's. He had not long turned 17 when he took the new ball against Sri Lanka in Galle and bowled Malinda Warnapura with his sixth delivery. He took six wickets in the match and then eight in two Tests in Australia. In the "home" Test against Australia in Leeds last year that marked Butt's first as captain, Amir finished with seven wickets to earn the man of the match award and Pakistan a famous, and unexpected, triumph.

Lord's, in August of last year, was just his 14th Test match and the figures of 6 for 84 he finished with in England's first innings were the best of his career – the day after the spot-fixing story filled the front page of the News of the World he was named Pakistan's player of the series. He had already become the youngest player to take 50 Test wickets, but he was also already ensnared by Majeed.

But it was not with Majeed alone whom Amir had become involved in suspicious activities with. Phone records from his Blackberry reveal contact with a number in Pakistan of someone who has never been identified. In August, prior to any of the plotting over the two Lord's no-balls, Amir messaged the Pakistan number, "For how much and what needs to be done?" Later he texted back, in Urdu, seemingly confirming something that had already been asked of him: "So in first three bowl however you want and in the last two do eight runs?"

Amir was to contact the Pakistan number again. After his room in the Regent's Park Marriott Hotel was searched on 28 August by officers of the Metropolitan Police, Amir used Majeed's phone to send a text to his contact in Pakistan. It read: "Amir here. Don't call my phone. ICC police have taken my phone. Are you able to delete those calls you made to me? If you can, do it OK. Don't reply." This, it was suggested in court by Butt's defence team, was evidence that Amir, later described by his own defence as a "simple villager", was not the "naïve and wholly innocent" teen.

Yesterday as he turned to Amir, the last of the quartet to be sentenced, Mr Justice Cooke echoed the words of Imran Khan, Pakistan's greatest cricketer. In a letter to the court Imran said that on meeting Amir he was "struck by his lack of sophistication". "You were," said the judge to Amir, "unsophisticated, uneducated and impressionable". "It was," said Aftab Jafferjee, QC for the prosecution, of the events of last summer, "a tragedy for the sport and a tragedy for him".