An anonymous witness has described how a young father had a row over a smuggled parcel with one of his alleged killers the day before he was stabbed to death at Pentonville Prison in Caledonian Road.

Jamal Mahmoud, 21, aka Kaos, was allegedly killed by three fellow inmates in October last year in a power struggle over contraband flowing into the north London jail.

Basana Kimbembi, 35, aka Bas, Joshua Ratner, 27, and Robert Butler, 31 allegedly armed themselves with weapons and went to the fifth floor of G Wing, where Mr Mahmoud was attacked in an area not covered by CCTV.

An inmate gave evidence at the Old Bailey anonymously behind a screen on Wednesday, with his voice modulated to disguise his identity.

The witness, going by the name of Bobby Dorset, told how he saw Mr Mahmoud arguing with Kimbembi, in a cell with Butler the day before the killing.

He told jurors: “They was arguing. It was over a parcel that came into the prison. What was what in the parcel.”

Dorset said he saw the defendant he knew as Bas hold up a hunter’s knife which was up to 15 inches long.

He said: “He pulled the knife out and told Jamal to get out of the cell.

“Jamal walked out of the cell after seeing the knife.

“As Jamal walked away he said OK we will see what happens,” Dorset said.

The defendants deny murder as well as attacking another inmate causing him grievous bodily harm. The trial continues.

Reporting by Press Association