Nato forces designated Gaddafi as a military target after the former Libyan leader’s forces started firing on civilians as they tried to escape Sirte in a convoy of up to 100 vehicles.
It is understood that RAF Tornados were patrolling over Sirte at the time of the escape attempt but were not directly involved in the operation.
Gaddafi had been under surveillance by Nato forces for the past week after an intelligence breakthrough allowed them to pinpoint his location.
An American drone and an array of Nato eavesdropping aircraft had been trained on his Sirte stronghold to ensure he could not escape.
Intelligence sources have suggested that in his last days Gaddafi broke his rigid rule of telephone silence and was overheard using either a mobile or satellite phone. Voice recognition technology would have instantly picked up any call that he made.
MI6 agents and CIA officers on the ground were also providing intelligence and it is believed that Gaddafi was given a code name in the same way that US forces used the name Geronimo during the operation to kill Osama bin Laden.
Since the fall of Tripoli in August, intelligence services have been searching for Gaddafi across Libya and beyond using agents, special forces and eavesdropping equipment.