Three British Muslim men pleaded guilty on Monday to conspiring to cause explosions, part of a plan prosecutors say would have involved smuggling liquid bombs onto airliners with the intention of blowing them up mid-flight.
The same three, and two others, also pleaded guilty to conspiring to cause a public nuisance by publishing martyrdom suicide videos, admitting their guilt in the final stages of a major airline bomb plot trial.
Those who entered the pleas are among eight men on trial for the so-called Heathrow airport bomb plot, which was uncovered in August 2006 and led to the imposition of tight new restrictions on carrying liquids on board flights worldwide.
The jury must still decide if the remaining three men, and the five who have admitted guilt, are also guilty of the key charge of conspiring to murder thousands of people by carrying out the attacks on passenger jets bound for North America.
The changes of plea form part of the defence for some of the accused, who say that while they might have been planning to carry out explosions, and had made martyrdom videos, they never intended to attack airliners or kill people.
Instead, according to Abdulla Ahmed Ali, the alleged ring leader of the plot, the men had planned to carry out a publicity stunt-type explosion - possibly at the Houses of Parliament - in order to draw attention to a documentary film they were planning to make criticising British and U.S. foreign policy.
"We never intended to murder anyone or to injure anyone," Ali told the court on the opening day of the trial last month. "We wanted something that would not just make a bang but also be considered serious and credible," he said.
The admissions of guilt were made in the closing stages of a trial at London's Woolwich Crown Court that started six weeks ago and is expected to conclude next week, when the jury is likely to be instructed to retire to consider its verdict.
Britain has seen a series of high-profile terrorism trials over the past two years, including the conviction of those responsible for explosions on the London transport system in July 2005 that killed 52 people, and a similar, failed plot two weeks later.
