The escape has raised uncomfortable questions for jail authorities
An Australian prisoner has broken out of a top security jail by losing enough weight to squeeze through a gap between the bars of his cell and a brick wall.
Robert Cole, 36, was serving time for armed robbery and assault.
He went into prison weighing 70kg and left it weighing 56kg, according to the Sydney Morning Herald newspaper.
Authorities at Sydney's Long Bay Prison were "obviously very embarrassed" by the escape, a prison official told the AFP news agency.
The government of New South Wales state has called for a meeting of top prison officials following the escape - the third from a state prison in the last week.
'Armed and dangerous'
Cole is believed to have lost his weight in a matter of weeks.
To aid his passage through the gap, he used an unknown implement to chip away at brickwork around his window.
Prison officials discovered he had fled on Wednesday morning, leaving puffed-up pillows under his blanket to give the impression he was still in bed.
A judge two years ago concluded he was too mentally ill to stand trial.
Police have warned the escaped man is dangerous and may well be armed.