A new processing centre in Kent where English Channel migrants are held for up to a week is “struggling” to cope with the influx of people, a union that represents Border Force officers warned.
Facilities at the site in Kent are inadequate, causing rising tension that has already led to the police being called and the centre running out of food and water, the POA union said.
The Home Office denied the claims.
The Manston immigration short-term holding facility is at the former Defence Fire Training and Development Centre in Thanet, and was opened by the Home Office in January 2022.
The union says the large number of people arriving during September meant the target of holding them at the Manston site for 24 to 48 hours is “purely aspirational”, with migrants staying for up to a week.
PA news agency analysis of government figures shows 7,961 people arrived in the UK after crossing the Channel in September.
The POA says the facility is a “significant improvement” to the Tug Haven processing site at the Port of Dover, but the Manston facility is struggling to perform its role and tension is rising.
Migrant crossings on the English Channel surge amid heatwave - in pictures
“A member working at the site likened the situation to a pressure cooker coming to the boil with a jammed release valve," said a spokesman for the POA.
She said the ability to move people on from the site in a timely manner was the pressure valve.
“We have had reports of incidents escalating, altercations between residents boiling over and resulting in injury, with police having to be called to the site to investigate assaults and provide support to staff," the spokeswoman said.
“The POA believe the failure to relieve this pressure sits at the highest level, with a government that has not provided a coherent response at pace to the increase in numbers of migrants crossing the Channel, and the strain that is putting on the facility.
“There have been days where the facility has run out of food and drinking water for residents.
“The marquees are crowded, levels of bedding on site have become inadequate, laundry facilities are inadequate, cleaning regimes are not adhered to, and issues have been raised around high levels of condensation within the marquees, which has led to mould and bacteria developing.
“We will today write to Charlie Taylor, HM Chief Inspector of Prisons, and urge his inspectorate to attend and assess the developing situation.”
Inside a refugee camp in Rwanda - video
Inside a refugee camp in Rwanda
Kent Police confirmed they had been called to the immigration centre twice in the past two weeks.
“We attended a site in Manston Road, Manston, at around 11.55pm on September 28 to assist the Home Office following a report a small group of people were being abusive. No arrests were made," a Kent Police spokesman said.
“Kent Police attended a site in Manston Road, Manston at 8.10pm on October 2 to assist the Home Office following a report a man had thrown a plastic bottle at another man.
“A suspect was arrested on suspicion of assault and was later released on bail while inquiries continue.”
The Home Office said it was “untrue” to suggest there had been shortages of food and water at the site, insisting migrants were offered hot food, fresh clothing, toilet facilities, sanitary packs and medical care.
UK's first Rwanda deportation flight cancelled - video
UK's first Rwanda deportation flight cancelled
“The continued rise in dangerous small boat crossings is causing an unprecedented strain on our asylum system," a representative said.
“Manston is resourced and equipped to process migrants securely and we will provide alternative accommodation as soon as possible.
“Despite the lies they have been sold by people smugglers, those entering the UK illegally via the Channel will not be allowed to start a new life here.
"These individuals will be in scope to be relocated to Rwanda under our migration and economic development partnership.”
Rwanda prepares for refugees - video
Rwanda prepares for refugees
