Immigration removal flights have departed from Britain with as many as three staff for every foreign national on board, a report reveals.
On one journey to Germany in June last year there were 90 escorting officers for 30 individuals.
Flights to Nigeria and Ghana in January 2017 and Pakistan in September had 135 and 106 staff for 61 and 54 returnees respectively.
The figures were disclosed in an assessment of charter flights used by the Home Office to facilitate enforced removals from the UK.
The Independent Monitoring Board Charter Flight Monitoring Team (CFMT) assessed a total of nine operations: four to Islamabad in Pakistan, two to Tirana, Albania, one to Germany, one to Lagos in Nigeria, and one to Accra, Ghana.
In its annual report for 2017, the CFMT said a decision to put all returnees on the Germany flight in restraints was "neither fair nor humane".
The charter to Germany was arranged under the Dublin Convention, which determines which EU member state is responsible for considering an asylum claim.
The monitoring team was satisfied those on the other flights were generally treated fairly, but it was concerned about some aspects of their treatment.
For example, the use of restraint appeared to be a "hasty reaction" to statements of unwillingness to leave, according to the report.
It found some returnees were "treated as commodities", penned for hours in coaches with inadequate sanitation, and described the practice of arranging removal flights for late at night as "inhumane".
CFMT leader Lou Lockhart-Mummery said: "The escorts generally behaved professionally and respectfully, except during the operation to Germany.
"Over the year we observed some aspects of good practice.
"However, we consider that the approach would be greatly improved if the dignity 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."
A Home Office spokeswoman said: "The dignity and welfare of all those in our care is of the utmost importance and the Independent Monitoring Board rightly observed that returnees are generally treated kindly and with respect.
"However, we are taking the concerns raised by the inspectors very seriously."
Measures taken to address the report's recommendations include the introduction of body-worn cameras for escort staff.
Staffing matters are kept under continuous review, the Home Office added.
Tascor was the Home Office's escorting contractor for the period covered by the monitoring team's report.
The service has since moved to another provider, Mitie Care & Custody, which took over on May 1.
Copyright (c) Press Association Ltd. 2018, All Rights Reserved. Picture (c) Steve Parsons / PA Wire.