British terror suspect Saajid Badat has admitted plotting to blow up a plane on its way to the US using a "shoe bomb".
Badat, 25, of St James Street, Gloucester, conspired with fellow Briton Richard Reid and a Belgian terrorist to make the bomb.
He trained as a suicide bomber but later backed out of the plot. Badat will be sentenced on 18 March.
At the Old Bailey, he pleaded guilty to conspiring to place a device on an aircraft in service.
More than 100 homes in Gloucester were evacuated during a police search of Badat's house in November 2003, the court was told on Monday.
The court heard he had agreed to be a suicide bomber with the intention of destroying a passenger aircraft while it was in the air en route from Europe to the United States.
He received training both in Afghanistan and Pakistan and had been given an explosive device designed to evade airport security and destroy an aircraft in flight, said Richard Horwell, prosecuting.
Mr Horwell said Badat had sent an e-mail on 14 December, 2001, four days after his return, "indicating he might withdraw".
"He had booked a ticket to fly from Manchester to Amsterdam in preparation for an onward flight to the United States on which the explosive device would be initiated," he said.
Badat was arrested in Gloucester following MI5 surveillance
"But he did not take that flight. We accept by then he had withdrawn from the conspiracy which by then he had been party to for an appreciable period of time.
"The device he brought with him to the UK was kept at his home. He had separated the fuse and the detonator from the plastic explosive."
The device was identical to that used by Reid when he attempted to bring down an aircraft in December 2001 on a flight from Paris to Miami, said Mr Horwell.
Intelligence services believe Badat had been conspiring with Reid, who is in jail in America for trying unsuccessfully to ignite a shoe bomb on board a US-bound jet.
Links were made from Belgian telephone cards found on Reid, which were said to have been used by Badat to contact Reid's terrorist contact Nizar Trabelsi, who is in prison in Belgium.
Badat was arrested at his home after surveillance operations by the police and MI5.
His guilty plea has been hailed as a victory by Deputy Assistant Commissioner Peter Clarke, head of the Anti-Terrorist Branch.
"Three years of intensive and painstaking international investigation brought us to the point where Saajid Badat had no option but to plead guilty to this horrendous offence," he said.
"We must ask how a young British man was transformed from an intelligent, articulate person who was well respected, into a person who has pleaded guilty to one of the most serious crimes that you can think of."