The chilling images that claim to tell the story of a tragic Hercules mission

The finger hovers for a moment over a small white metal box set on stony ground before pressing a black button with the Arabic numeral four beside it.

The finger hovers for a moment over a small white metal box set on stony ground before pressing a black button with the Arabic numeral four beside it.

Under the leaden skies of the desert, two streaks of fire race into the air, apparently destined for the cigar-shaped silhouette of an aircraft in the far distance. Then the aftermath: first a plume of black smoke, followed by an indistinct mass of burning wreckage merges first into the remains of an engine, then a large section of fuselage with two aircraft wheels behind it.

Everywhere there is flame.

If the images are to be believed, then they show the last moments of the Royal Air Force cargo plane that crashed into the Iraqi desert on Sunday afternoon. Caution was being sounded last night by military experts who said it could instead be a slick montage of previous attacks designed to maximise publicity.

But the intent of the footage was unmistakable. Unseen by the camera, the bodies of 10 servicemen who had been on a flight, described last night as "routine", lie as yet undiscovered. They had been on board a Hercules C-130K which lumbered down the runway at Baghdad international airport bound for the American base at Balad, 65 miles north-west.

In line with their training and war zone tactics, the pilots would have steered the plane up in a sharp spiral after take-off to gain altitude at the maximum rate and avoid the fate that ultimately befell them.

Flying at between 12,000ft and 15,000ft some 20 minutes after take-off, the plane with its nine RAF crew and unspecified army passenger, thought to be a member of the SAS, should have been in the safest stage.

A British military source said last night: "Take-off and landing are the times of maximum danger. Our experience in Iraq is that aircraft, even something as relatively slow as a Hercules, do not get blown out of the sky."

Shortly after 4.35pm local time (1.35pm GMT) on Sunday, it seems that changed. The chilling images broadcast around the world yesterday afternoon were presented by Iraqi militants as evidence of their ability to shoot down planes, then ensure maximum publicity with 20 seconds of footage purporting to show the deed.

Starting with the finger pressing the launch button, the video cuts to show rockets streaking into the air towards the indistinct blob of an aircraft. After jerky footage of buildings and palm trees, it shows a towering plume of smoke before finishing with a lingering pan of the supposed wreckage, fuselage, loading bay, burning metal and plastics as two men pick their way through it.

Military experts said the white control box was not a common control system for missiles used in Iraq. But they warned that if true, it showed a new and frightening level of military sophistication by the militants beyond their more rudimentary shoulder-launched weapons. Robert Hewson, an air weapons expert for the Jane's publishing group, said: "What appears to going on is a lot more sophisticated than the shoulder-launched systems.

"This could be a remote-controlled device that uses radar to search for its target. The Iraqi regime had such equipment but it was thought not much of it was serviceable. This C-130 would have been equipped with an array of counter-measures to avoid this type of attack. It could be it was a lucky shot or the militants have exploited a plane being due at the same time on the same route and shot it down with something we haven't previously seen."

The images of the missile launch were claimed to be from "the Green Brigade", which is one of the brigades of the 1920 Revolution Brigade, a military wing of the National Islamic Resistance in Iraq. The group emerged in the Sunni triangle in July 2003, but it is the first time that a "Green Brigade" has been mentioned.

A second militant group, Ansar al-Islam, also claimed the attack, claiming it had downed the Hercules with a anti-tank missile, a feat experts described as unlikely. A statement from the group on an Islamic website said: "Thanks be to God, the plane was downed and a huge fire and black clouds of smoke were seen rising from the location of the crash."

The reliability of the images was among several mysteries that persist over the tragedy. The Ministry of Defence insisted throughout the day that reports that the Hercules had been carrying members of the SAS were inaccurate.

But the refusal to confirm even the simplest details of the mission fuelled speculation that special forces were involved. The MoD also delayed releasing the identities of the British victims until today.

Wing Commander Trevor Field said: "Ground forces are trying to secure the position and search the site. It is hostile territory and the priority is looking for bodies. The ground troops don't want to sit in the open out there for long.

"The aircraft was on a routine mission. It may have been delivering spares or supplies. [The army casualty] may have been a passenger en route to another location in southern Iraq. I can only speculate.

The sole named victim of the crash, Flt Lt Paul Pardoel, from Australia, had been attached to 47 Squadron, based at RAF Lyneham, in Wiltshire. The squadron flies C-130Ks, an older generation of Hercules used by British special forces to insert troops into enemy areas with a crew trained to work with the SAS. Military sources indicated the plane was involved in a special forces operation but it had been a routine task, delivering freight.

The Pictures

THE FIRING PANEL: The control box which appears to launch the missiles was described by experts as "inappropriate" for an advanced guided missile. It is possible the firing panel, which carries Arabic numerals and has two connecting wires, is a cannibalised remote-control device attached to a missile battery. Tellingly, the camera fails to show the missile to which it is linked.

THE MISSILE IN FLIGHT: The second image appears to show the missile heading towards the Hercules. Military analysts have questioned the validity of this footage. Guided missiles tend to "wobble" or undulate slightly before fixing on their target whereas this rocket appears to head directly on its course, without any obvious deviation.

THE SECOND MISSILE: This projectile takes a significant period of time to launch after the first rocket and appears much smaller. Commentators said it could have been a shoulder-launched device separate from the first missile, indicating that the attack was by militants equipped with only rudimentary devices unlikely to shoot down a modern military plane.

THE WRECKED ENGINE: At first glance, this destroyed engine appears to be clear evidence that it is part of the C-130, showing what looks like a propeller shaft. But the engine is badly damaged and could equally have come from a large military helicopter. It also appears to be equipped with the afterburner of a jet engine.

THE DAMAGED LOADING BAY: The penultimate shot purports to show the loading bay of the downed Hercules. While this may be the case, military analysts said that it could also relate to any number of transport helicopters used by British and American forces. The image may have been taken from a previous crash.

THE MEN AMONG THE DEBRIS The final piece of footage appears to show men among the wreckage. If the aircraft crashed at 4.35pm local time, experts believe it is unlikely the images could have been shot in daylight. Nor could the footage have been taken yesterday morning as by then the site was being investigated by the military, who had closed off the area.