A jealous killer teamed up with five other family members to murder a rival sweetheart with a dreadful array of weapons, including a fire ax, one learned.
Jay Sewell, 18, was stabbed by a group of nine, including 20-year-old Daniel Grogan, after his ex-girlfriend Gemma Hodder began seeing the teenager.
Grogan reportedly spread his "poison" on friends and members of his "close-knit family" who were "armed to the teeth" when they met with Mr. Sewell last December.
The weapons they wore included knives, baseball bats and a four-foot-long fire ax, the court said.
Grogan, with his parents Robert, 57, and Ann, 54, his brothers and sisters Peter, 22, and Francesca, 29, his cousin Liam Hickey, 19, a 16-year-old boy that we do not can not name, Francesca's boyfriend, Jamie Bennett, 31 years old and another. Charlie Dudley, 25, denies Jay's murder.
They also deny that they caused intentional bodily harm to a friend of the victim, Charlie Pamphlett, 18, who was wounded on the scene.
The prosecutor, Timothy Cray, said: "Just before 10 pm on Tuesday evening, December 11, a young woman, Gemma Hodder, drove from her home to Lee, in the southeast of London.
"She made the trip because she was going to see her ex-boyfriend, Daniel Grogan.
"Gemma and Daniel were separated two months ago and Daniel had a very bad split, he was jealous and depressed – he just could not let Gemma go."
The jurors learned that Gemma had recently started a new relationship with Mr. Sewell.
"You will remember or be aware of the emotions around first love or jealousy when it comes to an end.And as vivid as these feelings may be, they do not tend to result in charges of murder at the Old Bailey", said Mr. Cray.
He described Daniel Daniel Grogan's jealousy as the "first drop of poison" and said, "When he [Daniel] discovers the new boyfriend, it seems that the poison has spread quickly to his family and friends who are sitting next to him on the dock.
"Once Daniel Grogan learned that Gemma had a new boyfriend, he threatened to kill Jay several times and he did not hide those feelings.
"Gemma is at the center of his anger and the threats he makes to Jay are detailed, repeated and clear."
The jury heard that on the night of December 11, 2018, the family group had waited for the arrival of Gemma and her new boyfriend around 8:30 pm.
Mr. Cray stated that there had been talk of an individual fight between Daniel and Jay, but that it was "the opposite of an individual attack – it was an attack planned.
"We have reason to believe either that they wanted Jay's death, or to hurt him badly."
When Gemma and Jay arrived, they were pursued by the numerous group, carrying weapons, was informed of the court.
"They left the road together, crossed a railway bridge and went to the place where Gemma and her friends were.
"They crammed themselves with weapons and in the end, Jay Sewell was indeed stabbed to death."
"The magnitude of the violence – the scale of the attack – was terrifying."
The post mortem examination revealed that Jay had been stabbed three times, two on the legs and one on the chest.
The chest injury had a depth of 12 cm and reached the aorta. His friend was also stabbed but survived.
Ms. Hodder managed to get to a nearby hospital by car, but her boyfriend could not be saved.
"We say the nine accused are jointly responsible for Jay Sewell's death and his friend's injuries," Cray said.
The Grogans, from Lee, in south-east London, Bennett, from the same address, Hickey, from Crown Wood Way, Eltham, the 16-year-old from Greenwich and Dudley without a fixed address, all deny the murder .
The trial continues.