A prisoner accused of murdering the disgraced former Lostprophets singer told guards they “could be talking to someone famous” after stabbing Ian Watkins in the head and neck with a homemade knife, a court has heard.

Rico Gedel carried out the attack on Watkins, who was serving a 29-year sentence for child sexual offences, in his cell at HMP Wakefield, a high-security prison, on 11 October, Leeds crown court heard.

Gedel, 25, then handed the makeshift weapon to fellow prisoner Samuel Dodsworth, who disposed of it, the prosecutor told the jury at the opening of the prisoners’ murder trial.

The attack, carried out moments after Watkins’ cell door had been opened that morning, lasted about 20 seconds, with 44-year-old Dodsworth acting as a lookout, said Tom Storey KC.

When asked after the attack whom he thought was responsible, Gedel said: “God.”

In the moments before his death, when officers who tried to save his life asked who had attacked him, Watkins “said something to the effect of ‘that little black fella’”, Storey told the court.

Watkins was a “particularly notorious and high-profile” prisoner, who had received threats from other prisoners including on the day before he was killed, said Storey.

Gedel, whom prison officers described as “perky” when they detained him after the attack, allegedly said “have a good night’s sleep Watkins lad” when he was taken past the cell where the former singer was receiving medical treatment.

Gedel told police he was jealous of “nonce prisoners” because they “got treated like royalty”, the court heard, and he thought it was disgusting to share a wing with sex offenders at HMP Wakefield, often labelled “monster mansion” because of the number of high-profile prisoners.

Though the stabbing was carried out by one man, prosecutors say the attack was “a joint offence” between the two defendants. Gedel and Dodsworth deny murder and possession of a makeshift knife in prison.

The court heard Gedel had been moved into the same wing as Watkins and Dodsworth the day before the attack, and “coincidentally” put in the cell next to Watkins.

On the morning of Watkins’ death, prison officers started unlocking the cells on B wing after 9am, and Gedel left his cell, but Watkins chose to remain inside.

Storey said: “At this time Gedel was, in all likelihood, waiting for a moment when the prison officers on the landing were out of sight, and when he would have an opportunity to carry out the planned attack on Mr Watkins.”

CCTV showed Gedel going into Watkins’ cell just before 9.20am and leaving 20 seconds later, before walking towards Dodsworth and passing him something. Dodsworth glanced at the item and put it in the pocket of his jogging bottoms, jurors heard.

Footage showed Watkins emerging briefly from his cell with blood visible on the neck of his T-shirt. Two workmen who were carrying out maintenance work in the prison saw Watkins was holding his hand to his neck and bleeding from a wound. They signalled for help and three prison officers ran towards Watkins’ cell, where he was bleeding from his injuries.

One officer used his radio to summon urgent help while pressing a towel against a “particularly large wound” to the side of Watkins’ neck.

Watkins, from Merthyr Tydfil in Wales, collapsed on to his bed and lost consciousness. Paramedics were unable to resuscitate him and he was declared dead just before 10.15am.

The trial continues.