A lorry driver died when he became trapped between two vehicles after the handbrake was not put on, an inquest heard.
David Brown, 57, from Ely, died after the incident at BCJ Taylor Haulage in West Row, Suffolk, in March 2017.
He was connecting the cab to a trailer when it started to move. He tried to get back into the lorry but it crashed with an adjacent trailer, crushing him between the door and cab.
He died at hospital from his injuries.
The inquest in Ipswich heard the incident was being investigated by the Health and Safety Executive.
The policy was for drivers to apply the handbrake in the cab and turn the engine off before attaching a trailer.
PC Andrew Fossey, a forensic collision investigator, said Mr Brown had "failed to carry out the correct procedure" and put that down to "human error".
He told the jury there was no fault with the vehicles, there was a slight slope to the yard but nothing significant and visibility was "excellent".
"Mr Brown either failed to apply the handbrake correctly or simply forgot," he said.
The incident happened at about 09:30 GMT on 13 March.
Mr Brown was taken to Addenbrooke's Hospital where he died.
He was a "qualified and experienced" lorry driver, who gained his licence in 1992 and had worked at BCJ Taylor for about 10 months.
In a statement read out by the coroner, business owner Barrie Taylor said it was the first incident at his company in more than 40 years.
He said everyone at the firm was "devastated" by Mr Brown's death.
The inquest continues.