Migrants arriving in Kent soaking wet and freezing after crossing the English Channel are being processed at what resembles a “rubble-strewn building site”, inspectors found.

Many were then detained for days at a time in rooms with no sleeping facilities, showers or access to the open air.

A surprise visit to Home Office facilities by HM Inspectorate of Prisons (HMIP) exposed a series of failures.

In one case a 15-year-old boy was held for more than 66 hours and records were not clear as to why this had happened.

However inspectors also found that detainees were almost all very positive about their treatment by staff.

Charities said the findings were “extremely disturbing” and show the “brutal reality of how refugee children are treated in Priti Patel’s Britain”.

Published on Friday, the report follows visits last month to short-term immigration detention holding facilities at:

– Tug Haven in Dover, where migrants were first taken from the beach or sea
– the Kent Intake Unit (KIU) in Dover
– Frontier House in Folkestone
– Lunar House in Croydon
– Yarl’s Wood immigration removal centre in Bedford

More than 7,400 people have made the perilous crossing to the UK by boat this year, according to analysis by the PA news agency.

When they first arrive in the UK, after either being picked up in the Channel or landing on beaches, they are taken to Tug Haven in Dover.

Peter Clarke, HM Chief Inspector of Prisons, said: “Detainees almost always arrived wet and cold, but then often had to spend hours in the open air or in cramped containers…

“Basic supplies, including dry clothing, ran out during the inspection and some detainees were placed on escort vehicles in wet clothes.”

The Tug Haven facility “resembled a rubble-strewn building site”, inspectors said.

They also found that there was “nowhere suitable” to isolate people displaying symptoms of Covid-19.

At the Kent Intake Unit (KIU) and Frontier House, some detainees were held for more than two days in rooms with no sleeping facilities, showers or access to the open air.

In one case, an 80-year-old woman travelling without her family was held for more than 40 hours.

Particular concerns were raised in relation to the treatment of children, many of whom were arriving on UK shores on their own.

In one case, a child was mistakenly taken to a detention centre for adults.

Some very young children in family groups were also held for far too long, inspectors said.

One family including a baby and four other children under 11 were held in Frontier House for 45 hours.

While numbers of migrants crossing to the UK in small boats have soared in 2020, Mr Clarke criticised a failure by the Home Office to plan “for what must have been a predictable increase”.

He said: “Just because numbers are unprecedented, that does not mean they are unpredictable, or cannot be planned for”.

Mr Clarke added that while numbers were far higher in 2020, the reception arrangements at Tug Haven were not fit for even small numbers.

Those detainees who were taken to Yarl’s Wood were received into a high standard of accommodation and reported that staff treated them well, the report found.

Mr Clarke said: “We met detainees who had been extremely traumatised after their long journeys, and their positive feedback on the decency shown to them by many individual staff cannot be underestimated.”

He called for “coordinated and strategic action” involving different Home Office agencies and the Dover port authorities.

This is an extremely disturbing report which sadly confirms our worst fears about the conditions into which vulnerable and often traumatised people are being placed

Bella Sankey, director of Detention Action, said: “Wet, cold, unaccompanied children detained in unacceptable conditions with adult strangers, no access to legal advice and little safeguarding, record keeping or basic health screening.

“This report reveals the brutal reality of how refugee children are treated in Priti Patel’s Britain.

“HMIP makes it absolutely clear that this is not a result of a rise in numbers, it is a result of her lack of care and action.”

Migrant charity worker Bridget Chapman, of Kent Refugee Action Network, said: “This is an extremely disturbing report which sadly confirms our worst fears about the conditions into which vulnerable and often traumatised people are being placed in once they arrive in the UK.

“This report doesn’t simply list one or two small issues; it is a litany of serious problems from people being transported in wet clothes, to being kept in inappropriate facilities with nowhere to sleep for more than two days.”

A spokesperson for Mitie, which manages KIU, Frontier House and Lunar House on behalf of the Home Office, said: “It’s positive to see the report acknowledge that our colleagues treat detainees with respect including the frequent use of interpretation services to support initial interviews.

“However, we appreciate there are still areas for us to work on.

“Following the publication of this report, and in partnership with the Home Office, we will continue to make improvements and look to implement the recommendations made.”

Responding to the inspection findings, the Home Office said it is “fully adhering” to its statutory duties to ensure facilities are decent and humane.

A Home Office spokesperson said: “We take the welfare of people in our care extremely seriously.

“We are fully adhering to our statutory duties to ensure our facilities are decent and humane.

“We have also improved both our facilities and the way we deal with arrivals in response to the unprecedented rise in small boat crossings.

“These crossings are dangerous, illegally-facilitated and unnecessary.

“We are committed to fixing the asylum system, to make it fairer and firmer, compassionate to those who need help and welcoming people through safe and legal routes.”