The men's arrests in August 2006 caused chaos in the global aviation industry and led to a strict security check regime - with a limit on how much liquids passengers can carry - that continues to this day.

'The intention was to perpetrate a terrorist outrage that would stand alongside the events of Sept 11, 2001 in history,' the judge said, calling the plot 'the most grave and wicked conspiracy ever proven within this jurisdiction'.

The trial heard that at the time of his arrest, Ahmed Ali, of Walthamstow, east London, had identified seven US and Canada-bound flights that were to be attacked within a two-and-a-half-hour period.

'Had this conspiracy not been interrupted, a massive loss of life would almost certainly have resulted - and if the detonation was over land, the number of victims would have been even greater still,' Henriques said.

The judge said that the plot had 'reached an advanced stage in its development', with the men in possession of enough chemicals to produce 20 detonators aimed at blowing up flights from Heathrow airport to San Francisco, Washington, New York, Chicago, Toronto and Montreal.