Migrants inside the packed Manston processing centre in Kent are threatening to self-harm and go on hunger strike in protest at being detained, Sky News has been told.
The Prison Officers' Association (POA) represents 170 people who are working at Manston as detention custody officers.
Andy Baxter is the assistant general secretary of the POA.
In an exclusive interview, Mr Baxter, who saw conditions for himself when he visited the centre 12 days ago, told us: "The unrest is spreading across the camp. Our members are facing threats from people constantly saying 'what's happening to me? Where am I going? When will I be getting moved on?'."
He went on: "When our members can't give them an answer, people start making threats to have sit-down protests, threats to go on hunger strike and people making threats of self-harm."
Mr Baxter told us his members have concerns for their safety.
He says there have been a "few incidents" of people making "weapons" from things like wooden cutlery and toothbrushes.
He said: "So far there are no incidences of those weapons being used on anyone - it seems to be something that people want to carry - but our members really are concerned."
Mr Baxter said he believes the army may have to expand its role, which currently involves 14 soldiers at Manston in a logistical capacity.
"Eventually I think we'll see a serious breakdown in public order," he said.
The Home Office won't say exactly how many people are inside Manston - but it's thought to be in the region of 4,000.
With record numbers of migrant arrivals on small boats across the Channel, about 30 marquees have been put up providing temporary accommodation - each half the size of a football field. Families are thought to be in former MOD buildings at the disused airfield.
Hundreds more people were moved to the Manston facility on Monday, following a petrol bomb attack at the Border Force migrant centre in Dover.
Manston is a processing centre where people are meant to spend a maximum of five days.
But it's turned into a detention facility because some have been there weeks, there is no accommodation such as hotels to move them to, and they can't leave until they have somewhere to go.
It's difficult to speak to people inside because they have had their phones taken from them.
But the charity Humans for Rights Network shared accounts with Sky News from two asylum seekers who were in Manston about a month ago.
The 16-year-old Sudanese teenagers are now in hotels in London.
One told us: "I spent 17 days in Manston. I slept on a blanket and was covered with another blanket which was not enough for me, and I was feeling cold. There were daily fights between people during my stay."
'You must help them'
The other said: "There were no beds in the tents, not even chairs. We used to put the food boxes on the floor and slept on them.
"I spent all the time in the clothes they gave me when I arrived, and they were wet with rain water. A skin disease spread during my stay, and I was afraid of getting infected with it.
"There are people still in this place, and they need medical care. The winter is harsh and there is no warm place to sleep. You must help them."
We can't independently verify these accounts, but Mr Baxter described the conditions he saw for himself during his recent visit.
He said: "I saw large marquees with quite poor facilities. Some of the marquees only had plywood floors.
"There were no seats. There was no furniture. There were no beds. People told me they were sleeping on the floor at night. They would sleep on a blanket.
"If they could get hold of cardboard, they would sleep on cardboard. It really was quite shocking to see people held in those conditions."