Overcrowding and staff shortages were largely behind the death of teenager Zahid Mubarek at Feltham young offenders institution, a major inquiry has found.
The 19-year-old was beaten to death by Robert Stewart just hours before he was due to be released from Feltham, where he was serving three months for theft.
Stewart, who is now serving life in prison for murder, was sharing a cell with the Asian teenager, even though Feltham had access to files telling of his violent past and extreme racist views.
Mr Justice Keith said today that a combination of "poor communication and shoddy practice" led to this situation, but "a core finding of the report was that malevolence was not involved."
He added: "At the heart of it all was a catastrophic breakdown of communications.
"Files went missing, information was not passed on, and when it was it was often not acted upon."
Previously it had been alleged that the two cell-mates had been deliberately placed together on purpose to create a fight, which guards could then bet on, in a practice known as "Gladiator". This was rejected by Justice Keith's inquiry.
He named the 21 members of staff that were "in some way to blame for Zahid's death" in his report.
Today's report is the result of an unprecedented decision by law lords to force the home secretary to hold a public inquiry into the killing.
One of the key findings was that such attacks are more likely to occur in failing prisons.
He called for either more resources to be given to prisons by government, or a change in policy to reduce pressure on prisons.
"One of the recurring themes throughout the report has been that such attacks are more likely to occur in prisons which are performing badly," Mr Keith says in the report.
The report adds: "There are many lessons to be learned from Feltham's decline, but the most important is that population pressures and understaffing can combine to undermine the decency agenda and compromise the Prison Service's ability to run prisons efficiently.
"When that happens, it is important for the Prison Service to tell ministers that, and they should listen very carefully to what he Prison Service has to say.
"The Prison Service will no doubt continue to strive to do the best it can with the resources it has.
"But if those resources are simply not enough, and the prison population continues to increase, ministers must find the extra money to enable the Prison Service to deliver a proper regime for the prisoners it is required to hold.
"If more resources are needed to ensure that our prisons are truly representative of the civilised society which we aspire to be, nothing less will do."
The Home Office said it was "determined" to put things right in the wake of this "terrible crime" and fully acknowledged that it should have been prevented.
"We failed in our duty to keep him safe," a spokesman said.
The Home Office added that it was acting on the recommendations made by Justice Keith.
"Many of the recommendations reflect policies and procedures already in place and we are examining the others carefully although we are mindful of the significant cost implications and the risk of weakening security or safety in other areas," the spokesman said.
"We have already placed a preliminary response to the 88 recommendations on the Home Office website which shows that we can accept, at least in principle, 50 of them at this stage."
However, opposition parties leapt on the critical report.
Shadow home secretary David Davis, said: "This report makes plain, serious failures in management made much more difficult by over crowding and the continuous allocation of prisoners to inappropriate prisons.
"It shows that the issue of insufficient prison places is not just about keeping dangerous criminals off the streets but also about making sure offenders who are imprisoned are done so in an environment that is safe and conducive to rehabilitation.
"It is absolutely vital that the government takes a grip of this issue and starts showing leadership in dealing with the issues of prison management identified in this report."
Liberal Democrat Home Office spokesman Nick Clegg added: "While some progress has been made to root out the problems identified by this and earlier reports, racism of any kind must not be tolerated.
"This report sets out nothing short of a complete transformation of the way in which inmate numbers and mental health difficulties are dealt with in our prison service.
"Justice Keith's conclusions must prompt the government to pull its head out of the sand and accept that we cannot keep filling our prisons to bursting point without devastating and potentially tragic consequences."