A 20-year-old woman died after her hair and clothing became "catastrophically entangled" in the drive shaft of a milling machine, a court has heard.
Lauren Scott was volunteering on a smallholding near Dawlish on 4 March 2017 when the accident happened, Exeter Crown Court heard.
She died at the scene from multiple injuries.
The land-owner Neil Carpenter, 45, of Dawlish, is accused of manslaughter by gross negligence, which he denies.
Miss Scott's hair and clothes were caught in the power take-off (PTO) attached to the machine and a tractor, the court was told.
David Sapiecha, for the prosecution, said the set up of the pre-WW2 milling machine in a barn on Springfield Farm was "inadequate and dangerous".
He said PTOs were frequently used to power machinery on farms with the power being provided by a tractor engine.
Mr Sapiecha said it was "fundamental farm safety" for the PTO shaft, which rotates at variable speeds, to be completely covered.
He said the PTO cover for the milling machine was "useless" because it was "dented and broken" and left some sections of the shaft uncovered.
Of Miss Scott he said: "Her hair and clothes at some point became caught, entrapped, in that PTO shaft and the effect was instantaneous and catastrophic.
"The power produced and the speeds obtainable make the system incredibly dangerous and there was no possibility of her pulling away or even reacting."
The court heard the force resulted in the 5'2" animal lover's clothes being ripped off her.
Traffic warden Mr Carpenter, who previously admitted two breaches of health and safety regulations by failing to ensure Miss Scott's safety on that day and in relation to two other people in 2015, later told police the milling machine was broken and should not have been used.
Mr Sapiecha told jurors Mr Carpenter, who he described as having a "cavalier attitude towards safety" had claimed he did not tell Miss Scott to, or did not know she was using the milling machine, but police had found a video taken by her which indicates he started the machine up.
"He lied and has been caught out by chance by that video," he added.
The trial continues.