The US Embassy in London was plunged into lockdown and bomb disposal experts carried out a controlled explosion after a bag containing wires and an iPad was left outside, a court heard.
Daniel Parmenter, 44, is on trial at the Old Bailey accused of making a bomb hoax outside the embassy in Nine Elms last November 22.
The court was told the defendant had denied intending to cause alarm, claiming it was just a form of “sophisticated graffiti art”.
Opening his trial on Monday, prosecutor Lucy Organ told how Parmenter had left the suspicious item in an alleyway by the embassy in south-west London, at around 6am.
At 8.30am, a civilian guard for the US Embassy was on a routine patrol when she noticed what she thought looked like a bomb and “panicked”, Ms Organ said.
She backed away, took a photograph of the suspected bomb and returned to the embassy to raise the alarm.
A police officer on duty at the embassy saw the photograph and walked down the alleway where he saw a drum, some photo frames, and a large metal tray with writing and a skull and crossbones on it, jurors were told.
Ms Organ said: “Next to all of this on the floor next to the wall was what appeared to be an IED, it was an old-style iPad with a key pad and firework wires all taped.”
As a result, a cordon was put in place, local roads were closed and the US embassy went into lockdown, the court was told.
Three bomb disposal officers attended the scene and carried out a controlled explosion.
The objects said to be left by the defendant included a piece of paper with “Danger Chemicals” written on it; a silver baking tray embellished with a skull and crossbones and the words “Warning Hazard” and a drum and drumsticks.
There was book of Wondercrump poetry in a frame, and a red picture frame containing assorted items including tools and a first aid kit, the court heard.
A box of dates was also found marked for the attention of the US Navy with the words “Do not X-ray, please inspect. Radiation. Hazard”.
An examination of CCTV from the area led to the identification and arrest of Parmenter at the home he shares with his mother two days later.
He told officers: “I presume this is about the framed toolkit that my dad produced and I dropped round as a gift for the US Navy.”
He denied meaning any harm, saying: “It is basically a form of slightly sophisticated graffiti art of the non-vandal type.”
Ms Organ told jurors that the defendant did not deny leaving the objects on the perimeter wall of the US Embassy.
The issue in the trial would be whether Parmenter intended others to believe the device was likely to explode or ignite and cause personal injury or damage to property, she said.
Parmenter, of Kildare Terrace, Bayswater, west London, has denied making a bomb hoax and the Old Bailey trial continues.
