Several people were concerned about the catapult's safety

Oxford University student Kostydin Yankov, 19, of Bulgaria, missed a net after being thrown 100ft (30.5m) from the medieval-style contraption.

He was at Middlemoor Water Park, Somerset, with a university extreme sports club when he died in 2002.

A narrative verdict was returned at the inquest in Taunton, Somerset.

Jurors found the incident may not have happened had catapult operators Richard Wicks, 34, of Burnham-on-Sea, Somerset, and David Aitkenhead, 46, of Fiddington, near Bridgwater, Somerset, imposed stricter safety measures.

The accident would probably have been prevented if a further set of tests had been performed

Jury foreman

Mr Yankov, a biochemistry student known to his friends as Dino, was one of five members of the Oxford Stunt Factory club to use the catapult on the day he died.

Known as a trebuchet, the catapult was a medieval siege weapon favoured by the Romans that hurled rocks over castle walls and plague-ridden bodies at the enemy.

A rope known as a strop that helped fire the mechanism was changed on the day of Mr Yankov's death, but not tested, jurors were told.

Thrill-seekers due to carry out stunts on the catapult were growing increasingly concerned that other jumpers were not landing in the middle of the net.

Cleared of manslaughter

Before Mr Yankov's jump, the weights that controlled the length of the rope were also altered.

He suffered multiple abdominal and chest injuries in the failed stunt and later died at Frenchay Hospital in Bristol.

Returning the verdict, the jury foreman said: "The accident would probably have been prevented if a further set of tests had been performed after changing the strop."

Mr Wicks and Mr Aitkenhead were cleared of manslaughter in connection with Mr Yankov's death in May 2004, on the direction of a judge due to a lack of evidence.