We need to make sure people from all backgrounds are treated fairly throughout the criminal justice system

Spokeswoman for Nacro

The formal investigation follows the racist murder of an Asian prisoner by his cellmate, and a damning internal prison service report on racism at Brixton jail in south London.

This is the third time in the past decade the Commission for Racial Equality has invoked its law enforcement powers, which form part of the act.

In 1994, it launched a two-year inquiry into the army, which resulted in changes in recruitment and the way in which discrimination complaints were investigated.

And in July, the commission began an investigation into the Croydon branch of the Crown Prosecution Service.

Racist letters

The murder of Zahid Mubarek last March is the most extreme racially motivated attack in recent times, according to the criminal justice charity Nacro.

Robert Stewart, the 19-year-old's cellmate, has since been sentenced to life. He had written a series of race-hate letters to friends before the attack.

Inmates complained of racist attacks and taunts

Yet a survey carried out by the charity earlier this year found that a sizeable proportion of black and Asian prisoners had been racially abused by staff or fellow inmates.

"It was a snapshot survey across the board - we went to male prisons, female prisons, and institutions for young offenders," says a Nacro spokeswoman.

Although prison rules say racism will not be tolerated, and places a duty on staff to report racist remarks and attacks, 78% of the officers surveyed said they had received no training on how to implement the policy.

One in 10 prisoners from ethnic minorities said they had been the victims of a racially motivated physical attack, while 12% said staff or other inmates had physically attacked them.

Three in 10 black prisoners, and half of Asians, said they had been taunted with racist comments.

"But the Prison Service has made a very strong commitment to fight institutional racism and asked us to provide training," the spokeswoman says.

She says that following the inquiry into the murder of black teenager Stephen Lawrence, it is essential that people from all backgrounds were treated fairly throughout the criminal justice system.

'Back to Africa'

Prisons Minister Paul Boateng and Prison Service director general, Martin Narey, have previously admitted that the service is institutionally racist.

Staff, too, complained of harassment

In the wake of this year's report into racism at Brixton Prison, Mr Narey vowed to work closely with the commission to eradicate all racism.

The report, which was passed to the commission, found that a small number of staff "sustained and promoted racist behaviour".

The report included allegations from black inmates that white staff had "told them to go back to Africa". In many cases, prisoners - most of them black - were locked in their cells for hours without authority.

Staff from ethnic minorities also said they had been victims of harassment and bullying by their white colleagues.

In one case, a junior governor joked that his colleague was able to understand the bongo drums. His only punishment was to be sent on a day-long race relations course.

And Claude Johnson, a black prison officer, said he suffered further victimisation when he returned to work after winning damages for racial discrimination.

Having spent more than three years off work after suffering a nervous breakdown, he has said: "The truth is, they did break me in the end."