Four alleged jihadists planned to execute British soldiers and policemen in drive-by shootings on mopeds, a court heard.
Tarik Hassane, 22, Nathan Cuffy, 26, Suhaib Majeed, 21, and Nyall Hamlett, 25, plotted terrorist murders on the streets of London after being inspired by Islamic State, it is claimed.
Jurors heard how 'hostile reconnaissance' was carried out on potential targets including a police station and army barracks.
The plotters were also said to have discussed buying a moped while stocking up on guns.
They were allegedly inspired by a 42-minute hate speech issued in September 2014 by IS spokesman Abu Muhammad al-Adnani al-Shami ordering followers to kill disbelievers in the West.
In it he said: "Strike their police, security and intelligence members, as well as their treacherous agents."
But the plot was foiled by anti-terror police who arrested the west London British Muslims before they could launch the attack, the Old Bailey heard.
Prosecutor Brian Altman QC said: "With their arrests, the police successfully disrupted a plot to kill a police officer, a soldier or possibly even a civilian, in one or more terrorist attacks which, if the plot had been allowed to run its course, would have resulted in a terrorist murder or murders on the streets of London."
Ringleader Hassan, a medical student in Sudan, allegedly pledged his allegiance to the Islamic State and identified possible targets.
When he was arrested on October 7 2014, more than a week after the others, officers found images of Shepherd's Bush police station and the Parachute Regiment Territorial Army Barracks in White City on electrical devices.
Hassane would issue instructions to his close friend, physics student Suhaib Majeed, 21, who was responsible for secret communications, jurors heard.
Cuffy who worked at The Money Shop, armed the plot, while Cleaner Nyall Hamlett, 25, acted as the middleman, the Old Bailey heard.
By the time of their arrest they had sourced a self-loading pistol, a magazine with ammunition, a silencer and Hassane and Majeed had discussed buying a moped for £2,000, it was said.
They also collected images, documents and 'grim videos' on their iPads, laptops and smart phones, the court heard.
On his iPad, Majeed had the beheading video of American journalist Stephen Sotloff, who was murdered by Jihadi John.
Hamlett had a 'glossy IS propaganda video' called 'The Flames of War', ending with gruesome images of captured Syrian Assad soldiers being forced to dig their own graves before they are shot by IS henchmen.
Hassane, of Princess Alice House, Dalgarno Way, North Kensington; Majeed, of Cherwell House, Church Street Estate, St John's Wood; Hamlett, of Hanwell House, Great Western Road, Paddington; and Cuffy, of Sandbourne House, Dartmouth Close, Notting Hill, deny conspiracy to murder between July 8 2014 and September 25 2014, and preparation of terrorist acts.
Cuffy, who stashed four guns and ammunition in his bedroom, earlier admitted four counts of possessing prohibited weapons and one count of possessing ammunition without a firearms certificate, but denies possessing them with intent to endanger life.
Hamlett has admitted to transferring a firearm and ammunition to Majeed, who has admitted to possessing ammunition and a prohibited weapon, but denies a further firearms offence.
The trial continues.