Five-year-old Lucas Latouche Mazzei died in March 2017 after choking on the stone at Henley Beach Primary School.

He had been watching a cartoon at the time, including during a brief period when a teacher left the classroom, leaving a support worker with a restricted view of the area.

Deputy State Coroner Ian White said that despite his known tendency to overeat and overfill his mouth, Lucas was left unsupervised for an unacceptable period of time.

White said that allowed him to get hold of the nectarine unsupervised and unobserved.

He ruled that had staff remained in the classroom during the whole time the boy was watching the cartoon, his death would have been prevented.

The coroner said Lucas’ death was “heartbreaking and tragic” and the distressing attempt to save his life had a marked effect on those involved.

“Lucas’ parents have been consumed by grief over the death of their precious little son that day,” White said.

At its opening last year, the inquest was told that when Lucas was noticed to be choking, staff stood him up and started banging his back to try to clear his airway.

By this time he had begun to turn blue around his lips and cheeks.

Staff also tried lifting him up by his legs so he was upside down as they slapped his back.

A defibrillator was retrieved but was unable to be used while CPR was not started until paramedics arrived.

Counsel assisting Emma Roper said it appeared the provision of first aid was hampered by communication difficulties, including problems with mobile phone reception.

The inquiry was also told that under current rules, teachers in public schools were not required to have first aid training.

White found that, under the circumstances, the efforts to save the boy were reasonable.

But he recommended all teaching staff be required to hold up-to-date qualifications in providing first aid assistance in an education and care setting.

He also called for the education department to review its policies on obtaining information about students with special needs and review the first-aid guidelines for dealing with a choking emergency.

Outside the court on Friday, Lucas’ mother Daniela Mazzei said the journey looking for answers about her son’s death had been “extremely hurtful, even cruel”.

“Lucas’ death did not receive the attention it deserved from the education department, even when we insisted on it,” Mazzei told reporters.

“Our grief will always be with us. His death could have been prevented.”

The boy was diagnosed with a rare genetic disorder, succinic cemialdehyde dehydrogenase deficiency, known to affect only about 350 people worldwide.

-AAP