A man was deported to Germany in just his underwear and wrapped in a small towel only to be refused entry and flown back to the UK, according to a report.

The incident was described as an example of “dehumanising authoritarianism” by a charity leader who hit out at the Government’s approach towards detainees.

Details of the episode, which took place in July, emerged as part of findings from the independent monitoring board (IMB), made up of volunteers appointed by minister to scrutinise conditions in custody.

The board’s charter flight monitoring team (CFMT) looks as at how detainees are treated as they are escorted from immigration removal centres (IRCs) and deported to other countries by plane.

His torso and legs were bare. He travelled to Germany in his underwear and the small towel

Among examples highlighted in its annual report for 2019, published on Wednesday, was the description of a man who “injured himself in his room as IRC staff came to collect him”.

The report said: “His injuries were dressed before staff, in full personal protective equipment (PPE), took him down to meet the escorts.

“His torso and legs were bare.

“A small towel had been wrapped around his waist, which did not completely cover his thighs.

“He travelled to Germany in his underwear and the small towel.

“He was presented in this condition to the authorities there.”

The team observed his “boxer shorts were partially visible” during the flight but he had refused the offer of clothing throughout.

The report added: “The German authorities refused to accept him. He then dressed, went back onto the plane and returned to the UK. He was taken to hospital, and from there to an IRC.”

The team said it “sought, but did not find, any evidence that anyone had considered inviting the receiving authorities onto the plane to make their assessment there.”

Bella Sankey, director of charity Detention Action, said: “Semi-naked, self-harming, detainees being deported in the dead of night with unjustified force.

“This is the independent evidence on how Boris Johnson’s Government operates its shadowy charter deportation flights.

“This is not One Nation Conservatism, it is dehumanising authoritarianism.

“Charter flights must be stopped.”

But a Home Office spokeswoman said: “Returnees will try many and varied ways to disrupt their lawful removal from the UK.”

The news comes after the policy on deportation flights was thrust back into the spotlight earlier this year after campaigners launched legal action in a bid to ground a jet bound for Jamaica.

Overall there was a “significant reduction in enforced removal by charter during 2019”, according to the report.

But the team said it “remains concerned” as it set out findings from checks on removals to France, Germany, Jamaica, Kosovo and Switzerland and the UK end of an operation to West Africa.

The team “expressed particular concern about the approach to three returnees who had just self-harmed in an attempt to thwart their removal.

“They were required to leave the UK that day nonetheless.”

According to the findings:

– There was “ill-judged” use of restraints in some cases

– “Patchy on-the-spot oversight” from the Home Office

– Lack of continuous access to professional interpreting services in some cases and “no evidence” of some detainees being “properly prepared for removal from the UK”

This is the independent evidence on how Boris Johnson's Government operates its shadowy charter deportation flights

– Returnees “enduring long periods of confinement” in coaches and being denied “dignity and privacy” whilst using toilet facilities.

CFMT chairman Lou Lockhart-Mummery said: “We observed empathetic responses to the needs of some individuals.

“The escorts showed good inter-personal skills when dealing with English-speaking returnees.

“However, we consider that the approach would be greatly improved if the dignity and vulnerability of the individual returnee was acknowledged in all aspects of the removal process on the day and if the use of force or restraint was consistently based on a well-judged individual risk assessment and was continually reviewed.”

The Home Office said staff were “rigorously trained to ensure the safety of returnees throughout the removal process”, any use of restraint or force on a charter flight was reviewed by officials and all detainees were provided information about the process.