He was reported to have been killed in November 2008 by a US missile strike against militants in Pakistan.

With thousands killed in the air, the explosions could have caused more devastation than the Sep 11 attacks on the US.

Home Secretary Alan Johnson said the plot had sparked the largest counter-terrorism investigation in Britain's history, known as Operation Overt.

Ibrahim Savant, 28, Arafat Khan, 28, Waheed Zaman, 25, and Donald Stewart-Whyte, 23, were all found not guilty of conspiring to murder by blowing up planes. Stewart-Whyte, from High Wycombe, was also cleared of a general charge of conspiracy to murder.

The jury failed to reach verdicts on general conspiracy to murder charges against Savant, from Stoke Newington, east London, and Khan and Zaman, both from Walthamstow.

An eighth man, Umar Islam, 31, from Plaistow, east London, was convicted of conspiracy to murder, but the jury failed to reach a verdict on whether he was involved in a plot to blow up aircraft.

Police installed a hidden camera in the Walthamstow flat used as a bomb factory and saw both Ahmed Ali and Hussain recording jihadist suicide videos denouncing the West.

The men's defence was that they had been planning a political stunt, including small explosions intended only to frighten people at airports.

These political demonstrations, they said, would be backed up by a documentary they were making about western injustices. The videos they had made were part of that documentary, they said.

The world's airlines were thrown into chaos in 2006 after the men's arrests, as security experts immediately introduced restrictions on liquids in hand luggage.