The man accused of hacking PC Keith Blakelock to death during the 1985 Tottenham riots wrote a rap, saying "we chop him all over", a court heard.
Jurors at the Old Bailey were told a prison officer found the poem while searching Nicky Jacobs's cell at a youth custody centre in 1988.
Jacobs, who was 16 at the time of the attack, had been serving a sentence for affray following the riots on October 6, 1985.
The hand-written poem was read out by prosecutor Richard Whittam in court yesterday.
It stated: "As long as I live I remember it was 1985 the 6th October...
"Me have de chopper we have intention to kill an police officer Pc Blakelock de unlucky f***er him dis an help de fireman...
"Who did an out an fire de fireman see we av come and decide to scatter but Pc Blakelock him never smell the danger but when we fly down upon him he start scream and holla everybody gather round and av pure laughter he try to head out but we trip him over he start beg for mercy bit it didn't matter him try to play super man....
"We chopper we start chop him on his hand we chop him on him finger we chop him on him leg we chop him on his shoulder him head him chest him neck we chop him all over when we done kill him off lord er feel much better...."
Mr Whittam also described statements from key witnesses to the attack.
Pc Blakelock's widow, Elizabeth, was in the courtroom to hear the evidence about the horrific wounds he suffered during the attack.
The jury was shown police photographs taken during the riots, some featuring Jacobs, who is now 45, on the Broadwater Farm estate.
The jury was also shown pictures of PC Blakelock's injuries, and the knife which lodged in the officer's neck up to the hilt.
Mr Whittam said a number of different weapons were used, including single and double-bladed knives.
The most devastating wound was to the side of his face, caused by a machete or an axe, the court was told.
Jacobs was first arrested by officers investigating the riots on October 11 1985, five days after the disturbances took place, the court heard.
He claimed that he had been at home when Pc Blakelock was attacked and had only watched the rioting, but was convicted of affray in November 1986.
One witness at that trial, who was himself convicted for his part in the riots and admitted kicking Pc Blakelock, told police that he had seen Jacobs at the scene and then talked to him days later.
Mr Whittam said the witness told police: "I can't remember exactly what he said but it was obvious from what he was saying that he was involved in the murder of the policeman."
Speaking to a renewed investigation into the killing in 1993, the witness went further and described the defendant as a "nutter" who was "out to get blood".
The witness, a former member of the Park Lane Boys gang, said he had seen Jacobs carrying a "curved machete or scythe". The defendant had plunged the weapon "crazily" into Pc Blakelock's shoulders as the mob shouted "Kill the beasty" and "Get his f****** head on a pole", the witness told officers.
Describing the murder he said: "They all had weapons and were involved in killing him.
"I know because I saw it with my own eyes. I have had to live with this for the past eight years, it's always on my mind."
The witness also claimed that the riots had been "pre-planned" and that the Park Lane Boys had stockpiled "weapons and petrol bombs".
And he told police that he had "nearly got killed last time for helping you lot" during the original investigation.
A second witness, known in the trial as Rhodes Levin, told the renewed investigation in the early 1990s that he had seen Jacobs stabbing PC Blakelock twice in the top half of his body with a "fairly small knife".
Levin, a drug dealer with convictions for selling heroin and crack cocaine, also claimed that the defendant had patted PC Blakelock's body down, looking for money or property.
When the pair were in Pentonville prison together in 1992, the witness claimed Jacobs told him: "I got a good couple of stabs in on the officer."
Mr Whittam also told the jury of seven men and five women that when he was held by police in May 2000, Jacobs allegedly told the arresting officer: "F*** off, I was one of them who killed Keith Blakelock."
It was only after Levin was given the promise of immunity that he admitted having kicked PC Blakelock himself five or six times.
During a third investigation into the murder which began in 2000, police left a note for another key witness known as Q, a long-term heroin user who had been living on the Broadwater Farm estate at the time of the riots.
In a witness statement given to police in July 2009, Q said he had known Jacobs all his life and saw him with a "mini-sword or machete type thing" during the attack, the court heard.
"PC Blakelock was on his back," the witness told police.
"I know this because his feet were pointing upwards.
"I was about 15 feet to the left of his body at the time of the murder.
"I saw Nicky Jacobs making repeated stabbing motions to the top half of PC Blakelock's body."
Jacobs denies murder. The trial continues.