More than 90 per cent of ethnic minority inmates insisted they had either been subjected to abuse or witnessed it. Many complained of beatings and bullying. One senior officer admitted it was only a matter of time before a similar murder happened again. Attacks against Muslim prisoners, the investigation discovered, were increasing. Many complained of being victimised. In several prisons, they insisted they had maliciously been given pork masked as Halal food.
A dedicated Prison Service helpline for staff subjected to racism was so inundated that it closed down for three months, citing on an answering machine that it was a "victim of its own success".
The findings appear to contradict the report by the inquiry chairman, Mr Justice Keith, that changes were taking place though "much still needed to be done".
"To suggest that six years after Zahid's death things have changed is fanciful," said Imran Khan, the family's solicitor.
Imtiaz Amin - Mr Mubarek's uncle - said he found it chilling to hear one white prisoner relate how he was deliberately placed with black cellmates despite claiming he was racist. The family has long questioned why the Asian teenager was incarcerated alongside a psychopath with a long history of convictions and open hatred of ethnic minorities.
"One man told us that when he arrived at a prison, he was asked whether he was racist, anti-religious or homophobic. He said 'yes' because he thought he would get a single cell. He was immediately put into a cell with two black guys," said Mr Amin.
In a series of prison visits over the past few months, Mr Amin as well as the race expert Suresh Grover, of The Monitoring Group, interviewed staff and prisoners. They found any efforts to combat bigotry were usually half-hearted and disorganised.
Yesterday - in a confirmation of their findings - the Home Office was unable to provide any figures for race attacks in jail, insisting that they were not categorised by motivation.
"Only in one prison were we given the impression that the governor was serious about tackling the problem. It was the only one with a full-time officer dealing with the issue," said Mr Grover, who said he was shocked to discover there was no manual laying down a process for investigating hate crime.
"The culture of racism and religious discrimination is far worse than I ever thought it was."