A grief-stricken father who accidentally hit and killed his young son with a 100-tonne truck has broken down while reading a heartbreaking letter at the boy's funeral.
Doug Sproule, 38, was parking his truck in his workplace yard in Picton, south-west Sydney, on May 22, unaware that five-year-old Harrison was behind the vehicle.
Despite the best efforts of paramedics and Liverpool Hospital staff, the boy died on the day of the accident.
On Tuesday, hundreds mourned the loss of the young boy who was remembered for his love of trucks and travel, 7 News reported.
Harrison Sproule, five, was killed on Friday afternoon after his father accidentally hit him with his truck in Picton, south-west Sydney
A teary-eyed Mr Sproule read a letter, addressed to his dead son, to family and friends at Camden Baptist Church.
'Dear Harry,' the letter began.
'You lived your life to the fullest, full of adventure with your two brothers and big sister who loved you dearly.'
It's believed the five-year-old became stuck in between his father's truck and another vehicle on Friday afternoon
Harrison loved riding in the truck with his father and was close with his two brothers and sister
'Your mum and dad will miss you. We will see you again. Keep trucking, little man.'
Also known to close friends and family as Road Train Harry, the youngster spent most of his short life travelling alongside his father in a truck - venturing as far as Darwin and Western Australia.
Harrison's body was driven from the church to the cemetery in a heavy-duty Kenworth truck - a vehicle manufacturer the boy could recognise from the age of three.
Most family and friends watched the funeral service via a live stream from the path outside Camden Baptist Church due to COVID-19 restrictions.
Harrison's body was driven from the church to the cemetery in a heavy-duty Kenworth truck
Just a day after the accident, Mr Sproule told the network he blames himself for the horrific accident.
'It's my job to protect them and I failed on this one,' the father-of-four said.
'Sorry is all I can say. I fix problems every day but I couldn't fix this one.'
Harrison's sister Claire and brother Max sat in tears beside their father as they reassured him he wasn't to blame.
Harrison's father Doug Sproule (middle with daughter Claire and son Max) said he blames himself for the horrific accident
'You don't have to be sorry, it was an accident,' Claire told her father. 'You didn't fail.'
Mr Sproule said he 'loved' riding in the truck and would try and stay awake with him through the night.
It's believed the five-year-old was winched in between his father's truck and another vehicle.
Harrison was rushed to Liverpool Hospital but tragically died on May 22