FIVE British service personnel killed when their helicopter was shot down by a missile in Iraq may not have known they were under attack, an inquest heard today.

The Lynx helicopter - carrying Benson-based Flt Lt Sarah Mulvihill, 32, and Wg Cdr John Coxen, 46 - plummeted out of the sky on to the roof of a building after it was hit.

Eyewitnesses reported seeing the aircraft "jolt" to one side and told of smoke trails leading to the helicopter at the time it exploded.

The four men and one woman had been on a slow-flying mission to identify possible landing sites in the southern city of Basra, when they were targeted.

Crash investigators told Oxfordshire assistant deputy coroner Andrew Walker the attack had been so sudden the crew had not had a chance to react.

Capt Stephen Daniels, a Royal Navy pilot who has 31 years' flying experience, led the military Board of Inquiry into the incident.

Responding to the eye-witness reports, he said: "Had it been described as a rapid turn and the nose-dropping rapidly and the aircraft turning rapidly then I would have deduced it was the start or the whole of an evasive manoeuvre."

However, he said the Lynx had been hit so soon after it had begun to move, he could not be sure of the pilot's intentions.

He suggested the pilot might simply have been beginning to turn to get a better view of a possible landing site when the missile struck.

Lt Cdr Michael Abbey, a Royal Navy accident investigator, told the inquest in Oxford how the missile had hit the Lynx half-way along its right-side jet engine. Three other crew members were also killed in the crash, on May 6, 2006.

The inquest continues.