Every night for the past two weeks, Hadi has woken up in his cell in Harmondsworth immigration removal centre gasping for breath and clutching for his inhaler. Sometimes he shouts out to the guard for help, convinced he’s suffocating.

“I have dreams of people killing me, with their hands around my neck,” he says. “At the moment I sleep maybe two or three hours a day. Thinking about all this, the virus … I feel down now … really down, to be honest.”

Since the outbreak of coronavirus, Hadi (not his real name) has been experiencing frequent night terrors, leading to panic attacks and an increase in asthma attacks.

“My chest always feels tight, but now I am having an attack once or twice every time I wake up,” he says. “We live, 30 of us, close together. I don’t know these people. Maybe they got it but they don’t know it.”

In the past week four members of Hadi’s wing in the centre, near Heathrow airport, have been quarantined. There have been unconfirmed reports of one detainee there testing positive for Covid-19 and being released, according to the campaigning group Bail for Immigration Detainees.

Dr Mary Kamara, a nurse working with the charity Medical Justice, says detainees like Hadi are at particular risk of contracting the virus.

“If a patient with a severe respiratory condition catches coronavirus, their life could be at risk,” she says. “Patients with existing respiratory health conditions such as asthma should be released. If the government insists on vulnerable people staying in detention centres, they should be isolated.”

Medics are also concerned about the mental health of detainees, with some reporting that care facilities are being used to segregate those with existing mental health conditions, alongside those with symptoms of coronavirus.

“Psychologically, almost everyone leaves worse than when they came in,” Kamara says. “Anxiety and depression and a tendency to isolate turns to suicidal thoughts and self-harm. If you add uncertainty, a lack of information, physical isolation and health concerns, there are considerable mental health risks to deal with.”

Hadi, who sees a psychiatrist once every three weeks following episodes of psychosis, says his mental health has suffered since the outbreak started.

“They increased my pills three weeks ago but they don’t do nothing. I’m always thinking about it – every minute, it’s on my mind. No one can do nothing to help.”

The government’s guidance states that a number of measures should be introduced to ensure the safety of detainees with underlying health conditions, including the provision of protective masks and sanitiser and close monitoring of vulnerable individuals.

“Psychologically, almost everyone leaves worse than when they came in

“I saw maybe one or two people with masks,” Hadi says. “No one offered me one. No hand gel, only shower gel to wash our hands.”

He also says there have been no instructions about social distancing. “We share everything. We shower together, we eat together – maybe five to 10 people on a table – and we speak together outside in the yard. No information. Nothing has changed since coronavirus.”

The government says it has taken “sensible, precautionary measures” to prevent the spread of the virus in immigration removal centres (IRCs).

“The safety of detainees and staff is of vital importance,” a Home Office spokesperson says. “Detainees arriving at an immigration removal centre are medically assessed by a nurse within two hours of their arrival and a doctor within 24 hours. Handwashing facilities are available in all IRCs and we are working closely with suppliers to ensure adequate supply of soap and cleaning materials.”

But charities say that without universal testing in detention centres, coronavirus could quickly spread.

“They’ve put some people in isolation but they’re not testing them, so they must be putting some people in there that have it and they’re mixing with people who don’t,” says Emma Ginn, the director of Medical Justice.

It is also unclear whether those who are due to be deported will be tested. Hadi is due to be returned to his country of origin in two months, but Adam Spray, his case worker from Bail for Immigration Detainees, says there has been no guidance on this.

“It may be that the receiving country insists on it,” Spray says. “Given current travel restrictions and border controls, it’s difficult to see how the government can secure agreements with foreign embassies and enforce removals within a reasonable timescale.”

In the past week, more than 300 immigration detainees have been released from detention centres following a legal action which argued the Home Office had failed to protect or identify the most vulnerable. The high court ruled on Wednesday against the release of a further 736 immigration detainees, whose cases it said it would review to determine future releases.

For Hadi, who is gripped by fear of catching the virus, the potential for imminent deportation and worsening mental health, little can reassure him. “I’m not safe to be here. There’s too many people; we don’t know who has it. I only want to be safe … to be healthy.”