AS two Libyans are about to stand trial in Holland for the Lockerbie bombing, there is still speculation that the disaster was in fact a revenge attack carried out by Iranian extremists.

The blowing up of Pan Am flight 103, in which 259 died, happened six months after an American missile cruiser in the Persian Gulf shot down an Iranian airbus carrying 290 people on a commercial flight to Dubai; everyone on board was killed.

The ship was known in the American fleet as "Robocruiser", because she was said to be "trigger-happy". Tonight a BBC documentary investigates why the USS Vincennes came to fire two heat-seeking missiles at the Iranian aircraft.

The programme's makers had access to secret intelligence documents as well as official US Navy film taken on board that day. They also spoke to former senior figures in the American military who are appalled at the events and subsequent cover-up.

David Carlson, who was captain of the Vincennes' sister ship, USS Sides, states baldly: "I view the entire affair as a gigantic screw-up. We should have held people accountable and I believe we should have apologised to the Iranians. Had we apologised, Lockerbie might not have happened."

As it was, the American government attempted to shift partial blame to the Iranians - while Captain Will Rogers, commander of the Vincennes, was decorated with the Legion of Merit Medal.

The Vincennes was part of an international task force sent to the Gulf to protect western oil tankers during the Iran-Iraq War. But the programme claims that the Americans were pursuing their own secret agenda in support of Iraq. US ships sank half the Iranian navy and destroyed Iranian oil platforms; in effect, American military intelligence was waging a covert war that undermined the commanders in the field - and this led eventually to the airbus tragedy.

On July 2 1988 the Vincennes responded to a "distress call" from a Gulf oil tanker and the sound of "explosions". She sent a helicopter to investigate, which claimed it had been fired on by armed Iranian speedboats.

Neither the call, nor the source of the explosions, has ever been identified, but the Vincennes not only fired on the speedboats, it also entered Iranian territorial waters - a fact that was not officially admitted until four years later.

While this was happening the airbus took off for Dubai. The Americans later claimed that the Vincennes believed the aircraft to be an Iranian F14 fighter. They also said that the ship issued three warnings, although since two of these were on military frequencies, the civilian plane could not have received them.

On the Sides, Captain Carlson worked out that the speed and upward trajectory of the Airbus meant that it constituted no threat. The Vincennes, however, decided to "take it out".

Later, those interviewed on board the ship claimed to a man that the aircraft had been "descending" towards the Vincennes.

Officially, neither the plane's black box nor cockpit voice recorder was found. But the programme's makers have seen a CIA document about the recovery of black boxes in the Persian Gulf; five pages had been blacked out, leading presenter and co-producer Tim Hodlin to speculate: "It may well be that the Americans recovered them, and what they revealed did not support their case."

Admiral Dennis Brooks was commander of American, British, French and Dutch forces in the Gulf. He insisted on acting only on written orders directly from the President after becoming increasingly frustrated and alarmed by what he saw as interference from American military intelligence trying to promote a covert war against Iran. A power struggle resulted in his being moved from his command three months before the airbus incident.

"The fact of the matter is, we weren't running a script for a Sylvester Stallone movie out there", he says today. "We were conducting legal military operations as a neutral power in the middle of two warring nations."

The CIA has often been accused of aggressive interference in global affairs, and the Admiral says that where this undermined military operations it needed to be "fixed", adding: "We have a constitution; we wrote down what our rules were, and we told the whole world. We ought not to be down in the weeds trying to conduct illegal operations in front of the world."Correspondent: The Other Lockerbie, BBC2, tonight at 6.45 pm.
© Express Newspapers, 2000