A hammer attack suspect who allegedly left a teenager in a coma has walked free after the victim’s friends refused to give evidence in court.

Mohammed Hassan, 27, of Hathaway Crescent, Manor Park, was said to have repeatedly battered Arafath Rahman around the head with a claw hammer and allegedly left the 17-year-old for dead.

Prosecutors claimed Hassan was part of a gang of up to ten armed thugs who attacked Mr Rahman and his friends as they celebrated the end of Ramadan. Mr Rahman, now aged 21, suffered a series of injuries including a 2cm deep depression fracture to his skull and fell into a coma after the incident in Ilford.

He later regained consciousness but has been told by doctors that he is unlikely to ever fully recover from his injuries, Snaresbrook Crown Court was told. But four key witnesses to the attack, who were also assaulted in the Griggs Approach flyover car park in December 2007, all failed to come to court to give evidence. It is the second time the case against Hassan has collapsed after a first trial was abandoned last year amid allegations that a prosecution witness had been nobbled.

Now Mr Rahman’s friends, who originally identified Hassan and his pal Shorif Khan as the attackers, are being hunted by police after Judge Simon Wilkinson issued arrest warrants.

Khan, also 27, was cleared following the first trial after prosecutors dropped charges. Hassan was cleared on the direction of Judge Wilkinson.

Naming Forhad Uddin, Moinul Miah, Saif Uddin and Abdul Lotif, Judge Wilkinson said: “This week I issued warrants for their arrest. Respectively, witnesses may not wish to turn up, nevertheless their attendance is vital for the administration of justice.

“It is clear to me that they are in breach of that duty.”

The trial heard Mr Rahman was rushed to Royal London Hospital where he remained in a coma. Detectives originally launched a murder enquiry after being told he was unlikely to pull through. He later regained consciousness and was transferred to the Royal Hospital for Neuro-Disability in Putney, but remains permanently paralysed.

Hassan, of Glen Park Road, Forest Gate, was cleared of causing grievous bodily harm with intent and violent disorder. Khan was cleared of the same charges last year.