I was on Manus Island last week to mark a dark anniversary – six years of indefinite offshore detention.

On July 19, 2013, the then prime minister, Kevin Rudd, announced that people who arrived in Australian waters seeking asylum would be detained indefinitely in offshore centres.

And so began long years of deprivation for thousands of innocent people in island prison camps.

They have been murdered, assaulted, raped, fired at with machineguns and shotguns, laid siege to after being cut off from the essentials of life, and brutalised under a prison system designed to dehumanise.

All of which occurred after they fled persecution in their homelands.

It’s been a shameful and bloody chapter in Australia’s story. And it’s not done yet.

When I arrived on the island last week, the first thing I noticed was how quiet Manus is these days. In previous visits, there had been dozens of refugees waiting to meet me when I arrived.

This time, there were none.

I asked my friend, Kurdish–Iranian journalist Behrouz Boochani, where everyone was, and he told me there were fewer than 150 refugees left on the island. Most of them no longer leave their rooms, due to the depression and despair that have set in since the Australian election.

Before I arrived on Manus, I emailed Papua New Guinea’s chief migration officer to ask for permission to visit the facilities. I heard nothing back.

So Behrouz and I decided to go together to the East Lorengau Refugee Transit Centre, so I could see the conditions there for myself.

Every day this saga drags on, more damage is done to innocent human beings. We cannot call ourselves a civilised country while this is being done in our names.

We walked up the public road to the gates, and I politely asked the attending immigration official if I could go in with Behrouz.

He asked to see my passport, so I handed it over.

He took it and invited me, aggressively, to leave the country.

I said I was not going anywhere without my passport, but he simply walked through the gates and into the prison with my passport in his hands.

And so began a little sit-in beside the road.

After about half an hour, the official came back and returned my passport. Again, he told me I had to leave PNG.

Shortly afterwards, Behrouz and I were walking down the main road when a police vehicle carrying four heavily armed members of the infamous mobile squad pulled up next to us.

I again surrendered my passport on request, and was told to get into the vehicle. I asked whether I was under arrest. They said I was not, and so I refused to get into the van.

I was again told I had to leave the country.

I said I did not regard that instruction as an official deportation, to which they replied I was free to go but they would come to my hotel later in the evening. Later I was visited by two immigration officials and told once again that I had to leave.

I figured I had ridden my luck far enough, so I caught the next flight out. And I left behind a humanitarian catastrophe.

From the murder of Reza Barati to the sexual abuse of children on Nauru, the lives of some of the most persecuted people on the planet have been destroyed by a bipartisan policy of deliberate cruelty.

I was on Manus two years ago when the Australian government closed the offshore processing centre at Lombrum.

At Australia’s command, food, water, electricity and medicine were cut off from more than 600 vulnerable people. They bravely stayed for weeks before they were beaten out by local police wielding metal batons.

Since then, things have only worsened. When it became clear the Coalition had won the election in May, most of the detainees felt an unspeakable despair. There have been multiple attempts at self-harm. One man who tried to set himself alight was charged with attempted suicide.

When I returned to parliament this week, I asked those MPs who continue to back offshore detention to go see for themselves what their policy has done.

I suggested that while they are there, they should have the courage to look in the eyes of the men and women they have detained and tell them why it is worth it.

I doubt any will have the courage.

It suits both Labor and the Coalition to have their political prisoners as far from sight as possible.

Manus Island and Nauru were not picked at random. Their remoteness and difficulty of access underpin the entire offshore detention regime.

Excluding journalists and observers means the Australian public are excluded along with them.

We are only offered the faintest glimpses of what happens inside offshore detention. Because when the Australian people actually see what is going on, they are horrified.

When The Daily Telegraph obtained photos of children being detained on Nauru, the subsequent Kids Off Nauru campaign resulted in every child being brought to Australia.

But the exile and political imprisonment of innocent people serves the government in a far more sinister way.

The entire regime of deterrence is based on the premise that life in offshore detention is worse than the conditions people are fleeing.

People escaping some of the most dangerous and hostile places on Earth must be reminded that nothing but brutality awaits them.

It is akin to mediaeval cities hoisting bodies on their walls to serve as a warning to other desperate people that they should not try to enter.

And Australia’s practices of immigration detention and boat turnbacks are starting to be mimicked by other countries.

Donald Trump’s detention centres have rightly been called concentration camps, and even moderate Democrats are fighting to end the regime.

In Europe, our government’s “No way: You will not make Australia home” campaign is so admired by neo-Nazi groups that you can often see posters bearing the same slogan and imagery at their rallies.

Every day this saga drags on, more damage is done to innocent human beings.

We cannot call ourselves a civilised country while this is being done in our names.

We cannot let Scott Morrison and Peter Dutton off the hook for what they have done to so many innocent people.

We also cannot ignore Labor’s moral cowardice on this issue. They have made the decision that compassion loses elections, despite the evidence to the contrary.

The only election in which Labor has secured majority government in the past 25 years came with a promise to end offshore detention.

They continue to underestimate the Australian people. Falling into line with the conservatives just makes real change all the more difficult.

For humanity’s sake, every person still stranded on Manus Island and Nauru must be given the freedom and safety they so desperately need.

PNG’s new prime minister, James Marape, this week met with Morrison in Canberra and demanded Australia lay out its time line to end offshore processing on Manus Island. PNG no longer wants to house a regime that its Supreme Court long ago ruled unconstitutional.

Despite this, the government is pushing ahead with its plan to repeal the medivac legislation, laws that have undoubtedly saved lives.

For their part, bar those with family in Australia, most of the people I have spoken to in offshore detention no longer want to come here.

So cruel is their treatment at our country’s hands that they could legitimately claim asylum from Australia.

In the face of all this, it beggars belief that Morrison will not accept New Zealand Prime Minister Jacinda Ardern’s kind and generous offer to resettle people.

Under John Howard, most people who were detained on Nauru were resettled in New Zealand and Australia.

That Dutton and Morrison cannot comprehend doing the same shows just how much they have poisoned the well on this issue.

Morrison says he cries and prays for the people he is detaining.

He can save his words, and his tears, and end it all with a simple phone call.

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