Three Britons were found guilty yesterday of conspiracy to kill using homemade liquid bombs, but a jury failed to agree that they intended to blow up transatlantic airliners in an al Qaeda-style attack.
The verdicts came after a high-profile, five-month trial in which prosecutors had argued that eight co-conspirators planned to smuggle explosives onto half a dozen aircraft at London's Heathrow airport and blow them up midway to North America.
After more than 50 hours of deliberation, the 12-person jury was unconvinced by the prosecution's description of a complex airline bomb plot, finding only three of the defendants - Abdulla Ahmed Ali, Assad Sarwar and Tanvir Hussain - guilty of a lesser charge of conspiracy to commit murder.
The jury failed to reach a verdict on four other defendants and the eighth was found not guilty on all charges.
Sentencing is due to take place later.
The trial had been closely watched in Britain, where police and secret services described the plot as potentially one of the deadliest ever hatched on British soil.
US authorities said it could have killed as many people as the September 11 attacks on New York and Washington.
After it was uncovered in August 2006, thousands of flights around the world were disrupted and new restrictions were introduced banning passengers from taking liquids on aircraft.
The British government praised yesterday's verdict, but the fact only three of the eight were found guilty, and that the main charge failed to stand up, showed there was doubt in the minds of the jury about the full extent of the plot.
The prosecution had described Ali, 27, as the ringleader of the gang and presented evidence taken from him including a diary that contained what they said was a blueprint for an attack.
A memory stick owned by one of the suspects held detailed information about flights from Heathrow to US and Canadian cities, most of them departing between August and October 2006.
The bombs would have been made from liquid explosives based on hydrogen peroxide mixed with an organic component such as tang, a substance used to make soft drinks, prosecutors said.
While Ali, Sarwar and Hussain admitted planning to carry out an attack, they said it was intended merely to be a publicity stunt designed to draw attention to videos they had made denouncing British and US foreign policy in Iraq.
They said they had never intended to attack aircraft.
While some of the men were waiting for new passports, the prosecution presented no evidence that a viable bomb had been made, no airline tickets had been bought and there was little to indicate that an attack was imminent.
However, seven of the defendants had recorded statements on video laying out plans to commit a suicide attack. Some of those videos shown in court showed the defendants laughing and joking in between takes as they tried to get their lines right.
When the trial began, prosecutors said the plot centred on seven flights from Heathrow's Terminal 3, each capable of carrying between 241 and 285 passengers.
But recorded conversations between the gang, all British Muslims aged in their 20s, suggested that other terminals and possibly 18 suicide bombers might have been involved.