An inmate who was stabbed to death in HMP Pentonville was a 21-year-old who had recently become a father.
Jamal Mahmoud, from Enfield, north London, was attacked with a "hunting-style knife" on Tuesday. Two other inmates were critically injured.
Two prisoners, aged 34 and 26, have been arrested on suspicion of murder.
Following the attack, about half of the 200 prison officers at the jail passed a vote of no confidence in its governor, Kevin Reilly.
The officers claim they are unable to prevent the influx of weapons and drugs being thrown over the prison walls, while also monitoring prisoners, BBC London reported.
They have demanded talks with the deputy governor about reducing the number of inmates allowed in the yard at any one time and increasing the number of staff on prison landings.
The Ministry of Justice (MoJ) has yet to comment on the vote.
BBC home affairs correspondent Danny Shaw said he understood the knife used in the attack was "bigger than a Bowie knife but smaller than a machete". It has been recovered.
Mahmoud, who was of Somalian origin, was attacked on the fifth floor landing of one of the prison wings, before being thrown over the railings, falling about 30ft (nine metres).
The motive is not yet clear, although claims about a dispute between gangs or drug debts are being investigated.
Mahmoud was jailed for six years and six months in July as one of two gang members sentenced for hiding a loaded Skorpion machine gun and ammunition in a garden in Enfield.
He was already serving five-and-a-half years for a separate robbery.
BBC home affairs correspondent Daniel Sandford visited the family home of Mahmoud in Enfield where relatives confirmed he was the father of a 10-month-old child.
Mahmoud's cousin Aisha Salah, said: "I blame the prison, it's very disturbing. I just hope that place gets shut down as soon as possible because it's not safe
Surprised no posted a thread about this.
No sympathy from my side.
