Roger Cook, 51, approached two airport security staff on July 7, 2005 and claimed there was an explosive device in the south terminal. His claim came hours after suicide bombers had struck London's transport system and killed 52 people on three subways and a bus.
The two security guards concluded that Cook was drunk and did not initiate an evacuation of Britain's second-busiest airport, reports AP.
"It was in my view that only because of the astute actions by the airport security staff that this was a hoax that a real crisis was averted," said Judge David Rennie.
The head of the British army, Nick Carter, said that Moscow was capable of taking "hostile actions" against the United Kingdom and NATO much earlier than expected