Asylum seekers who were housed on the Bibby Stockholm barge have claimed the Home Office did not contact them even when some on board showed signs of suspected Legionnaires' disease.
In an open letter to the Home Office, seen by Sky News, one asylum seeker hit out at their treatment from the department, describing their move on to the barge as a "harsh tragedy".
The author - who was speaking on behalf of the 39 asylum seekers originally on board - said a sense of "isolation and loneliness" had gripped those who were moved off the vessel following the discovery of Legionella bacteria earlier this month.
The writer also claimed that one of the asylum seekers had attempted suicide, but added: "We acted promptly and prevented this unfortunate event."
"Currently, we are staying in an old and abandoned hotel," the author writes.
"The sense of isolation and loneliness has taken over us, and psychological and emotional pressures have increased significantly.
"We even lack the desire to live and perform any tasks. The absence of tranquillity, comfort and basic needs has become our daily concerns."
Legionella bacteria, which is commonly found in water, can cause a serious type of lung infection known as Legionnaires' disease.
The Home Office previously said that none of those on the barge had showed signs of having the disease and that they were being provided with "appropriate advice and support".
But in the letter, the author describes the "shock and fear" those on board felt following the Legionella discovery on 11 August.
It later emerged that people spent four days on board the barge after the bacteria was discovered and before they were removed by the Home Office as a "precautionary measure" - prompting a blame game about what the government knew and when.
Dorset Council has said Home Office contractors were notified about the results on Monday 7 August - four days before people were moved off the barge.
The council went on to claim a Home Office staff member was informed about the bacteria on Tuesday 8 August.
However, a government source previously told Sky News there is no record of this conversation, and claimed the Home Office only received a written notification about the Legionella on the evening of Wednesday 9 August.
Speaking to Sky News, Health Secretary Steve Barclay said ministers were informed about traces of the bacteria only on Thursday 10 August.
Asylum seekers 'displayed symptoms of Legionella disease'
In the asylum seekers' letter, the author writes: "Some of us displayed symptoms of Legionella disease, but no one responded to us, the Home Office did not contact us, and everyone was in shock and fear.
"In the afternoon of that day, as the last individuals to learn about this problem, we were informed that we would temporarily be moved to a new location, so that the ship's conditions could be reevaluated. We were compelled to comply with this request."
The government docked the controversial vessel in Portland, Dorset, last month, saying it would be able to house up to 500 male asylum seekers who had crossed the Channel in small boats.
They claimed the new accommodation would help save money for the taxpayer, with hotel rooms for migrants costing up to £6m a day.
But the scheme has faced fierce opposition from human rights campaigners, while opposition parties have dubbed it a gimmick.
The first handful of people were moved on to the barge earlier this month, but within days a Legionella outbreak was detected in the water supply, forcing them off the vessel.
In the asylum seekers' letter, the author says they have been "running from persecution, imprisonment and harsh tortures, with hearts full of fears and hope from the countries we were born in, to find safety and freedom in your country and our new refuge".
They said that despite being advised by certain organisations not to move on to the barge, they decided to follow the directive from the Home Office, "even though we felt that the ship was largely a place for troublemakers and lawbreakers".
"We are individuals who are tired of the challenges that have arisen and no longer have the strength to face them," they added.
Government accused of 'disastrous record' on asylum claims
The letter comes a day after the Home Office released its latest migration statistics, showing the backlog of asylum claims in the UK had hit a new record high.
The pressure on the system has sent the taxpayer bill for asylum to nearly £4bn a year - a figure Rishi Sunak has said is "unacceptable".
Meanwhile, Home Office figures showed that Channel crossings have topped 19,000 for the year so far, despite Mr Sunak's promise to voters that he would "stop the boats" bringing migrants across the English Channel.
Labour said the record-high asylum backlog amounted to a "disastrous record" for Mr Sunak and Home Secretary Suella Braverman, while campaigners called for claims to be processed more efficiently.
But the prime minister defended the government's progress, saying: "I think the current situation with illegal migration is simply ridiculous. It's unfair and it's unsustainable.
"That's why one of my five priorities is to stop the boats. And I really want people to know I'm working night and day to bring that about.
"And when I became prime minister, before I outlined my plan, the number of illegal migrants coming to the UK had quadrupled in just the last couple of years. But for the first time this year, crossings are down.
"They are down about 15% versus last year. That's the first time that has happened since the small boats crisis emerged. That shows that the plan is working."
In response to the asylum seekers' letter, a Home Office spokesperson said: "We are following all protocol and advice from Dorset Council's Environmental Health team, UK Health Security Agency and Dorset NHS, who we continue to work closely with.
"Further tests are being conducted and we intend to re-embark asylum seekers only when there is confirmation that the water system meets relevant safety standards. The safety of those onboard remains the priority."
Sky News has asked the Home Office specifically about the claim it did not contact asylum seekers when some on board showed signs of suspected Legionnaires' disease, but we have yet to receive a response.