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Estimates has also looked at the situation on Christmas Island, where the death of Iranian refugee Fazel Chegeni - re-detained under controversial circumstances and over the serious and repeated concerns of several senior public servants - sparked a riot in the centre.

Chegeni, who had been tortured in prison in Iran and had, doctors say, “exhausted his capacity to cope” in detention, escaped from the Christmas Island detention overnight on Friday, November 6. His body was found in bushland two days later.

Following his death, a riot in the centre caused about $10m damage.

Australian Border Force Commissioner Roman Quaedvlieg refused to tell estimates how it was that Fazel Chegeni escaped from the Christmas Island detention centre.

He would say only that “human fault” was part of the failure that allowed Chegeni to escape. “No-one” he pointed out, has managed to escape from the island.