Robert Stewart is serving a life sentence for the killing

Instead of sounding an alarm outside the cell or radioing, Malcolm Nicholson called from his office, the inquiry into Zahid Mubarek's death heard.

This gave Mubarek's racist cellmate Robert Stewart at least four minutes to continue attacking the 19-year-old.

Mubarek was killed at Feltham Young Offenders' Institute, London, in 2000.

He had been sent to the institute for three months for theft, and was just hours from release when he was battered to death with a table leg by Stewart.

Known racist

Witness statements given to the inquiry on Wednesday focused on the way prison staff dealt with the assault on 21 March, 2000.

I saw that he was injured around the head and covered in blood Feltham night officer Malcolm Nicholson

Night officer Malcolm Nicholson told the hearing he made his way to the pair's cell on the night after the cell bells started to ring.

"When I opened the flap to the cell I saw Mr Stewart standing slightly to one side of the door, it appeared that he was holding a stick, Mr Mubarek was lying on his bed," he said.

"When I looked closer at Mr Mubarek I saw that he was injured around the head and covered in blood.

"I must have realised at this stage that the injury to Mr Mubarek was serious but I was shocked and it had not really sunk in that his injuries could be life-threatening."

The inquiry heard that Mr Nicholson did not ring medics at the first sight of blood, but instead called senior officer Gerard McAlaney.

When the two officers returned to the cell, Mr McAlaney told Stewart to drop the stick and they entered the cell after he did so, Mr Nicholson said.

Radio up high

"Having had time to think about how I reacted, the only thing that I perhaps should have done differently was that I should have used my radio rather than have gone back to the office to use the telephone," he said.

Staff made other key errors on the night of the murder, according to the witness statements presented to the central London inquiry:

• Before the attack, Mr Nicholson was in his office with two doors shut, listening to the radio at a high volume.

• A call to the healthcare centre was not specified as urgent, so a healthcare officer attended without rushing

• As the call gave no details, the medical official arrived with the wrong equipment - plasters and bandages instead of a neck brace and oxygen

• Stewart was moved to a cell with a basin where he could have washed off some of the evidence

• It took approximately eight minutes before an ambulance was called for Mubarek

• The night patrol report sheets from that night were not secured and have been lost.

Mubarek, of Walthamstow, east London, died in hospital one week after the assault.

Stewart, 24, a diagnosed psychopath from Hattersley, near Manchester, is serving life for the murder. He has told the inquiry racism paid a part in the attack.

The inquiry aims to examine how Mr Mubarek came to share a cell with a known racist, and whether staff at Feltham were racist.