At the heart of the clinical failing around the treatment of Joel Cauchi — the man who stabbed to death six people at a Sydney shopping centre — was his psychiatrist’s discharge letter to his treating GP back in 2020, four years before the attack.

For the coroner, it was wholly inadequate, failing to inform Mr Cauchi’s GP of the psychotic symptoms — hearing voices, writing notes about satanic control — his mother said he was showing at a time when he had been deprescribed his antipsychotic medications.

As such, it failed to signal that Mr Cauchi was in need of urgent psychiatric review.

Although the psychiatrist who wrote it, Dr Andrea Boros-Lavack, later acknowledged its inadequacies, her letter’s contents have been pored over, analysed, criticised and condemned.