THE government’s system for monitoring companies it pays to run migrant detention centres has been called into question after a year-long freedom of information battle won disclosure of confidential “self-audits.”

The documents reveal how contractors are paid according to their own monthly performance reports. The Home Office has refused to say if it scrutinises the data submitted by the companies.

The Home Office was forced to hand over the files to the campaigning group Corporate Watch after the Information Commissioner decided there was “a very strong public interest” in doing so.

The majority of Britain’s immigration detention centres are run by private companies under multimillion-pound outsourcing deals. The firms are required to send monthly “self-audit” reports to the Home Office, detailing any contractual failings and penalties incurred. Despite the importance of such documents in measuring compliance they have never been made public. The performance reports, from May 2014, raise serious questions about the integrity of a “self-audit” system.

The government’s confidence in large outsourcing companies, particularly Serco, has been challenged by a series of scandals. Serco is being investigated by the Serious Fraud Office for overcharging the government on an electronic tagging contract. In another widely publicised failing, the company recorded prisoners as being delivered to court in time for hearings when they were not.

Recently the Chief Inspector of Prisons reported that some vulnerable female asylum-seekers detained at the infamous Yarl’s Wood centre were treated “like animals” and that their experiences had left them with anxiety, depression, disturbed sleep and mental health problems (M Star August 19).

The company in charge of Harmondsworth, Britain’s largest detention centre, was penalised for a “failure to make available full healthcare service” and delays with legal visits. At Colnbrook detention centre, contractor Serco failed to “observe key/lock security procedures” four times in 10 days. In one case, a “door leading from the gate house into the sterile yard was discovered in an unsecured state.” Another penalty related to a detainee being “incorrectly discharged from the centre.” On one weekend that month, Serco failed to provide the minimum number of staff. Data about the exact size of penalties incurred by the companies for these failures has been redacted, after government lawyers lodged an appeal with the information tribunal to permit the “withholding of sensitive contractual information.” The case is due to be heard later this year.

Contractors can provide significantly different levels of detail to the Home Office, because there is no standard template for the self-audit. The report lengths are arbitrary, with one contractor’s audit more than half the length than that of their rival. The GEO Group, which operated Harmondsworth, simply left blank a section titled “details of accepted failures” in their “monthly contract review tool.”

The Home Office has refused to explain what follow-up action it takes after receiving self-audit reports, raising concerns that the monitoring system lacks any integrity. The Home Office says: “Self-audit reports are part of a range of measures, including regular independent inspections, to ensure our contractors continue to provide safe and secure accommodation for detainees.”

However, Serco’s self-audit should have caused the Home Office alarm. Under the contract, Serco was required to provide full medical screening to all new arrivals. However, the figures show that 686 people in one month, or 72 per cent of arrivals, signed disclaimers to not see a doctor. The Home Office has failed to challenge Serco about this high number of disclaimers. Serco said that “this is fairly normal. All detainees see a nurse on arrival at the centre and are asked if they want to see a doctor the next day. It was not uncommon for a large number to say that they were fine, did not want to see a doctor and sign a disclaimer. Obviously residents are able to request to see healthcare at any point while in detention.”

But disclaimers enable the company to escape its contractual requirement to give a “full medical screening” by a doctor, and means that almost three-quarters of people in its custody and therefore under its duty of care were not fully checked on arrival for undiagnosed medical problems.

A protest inside Harmondsworth in May 2014 was 10 times larger than the GEO Group, its operator, told journalists. The self-audit report for that month shows that the centre manager knew the demonstration involved “up to 300 detainees,” nearly half of all inmates. The company had told the media that “a short and entirely passive protest took place at Harmondsworth involving between 30 and 40 detainees.” GEO said that it did not “consciously” make a false statement to the media. The protest was against the fast-track asylum system. The unrest quickly spread to three other detention centres across the country. Months later, the High Court found that fast track carried “an unacceptably high risk of unfairness” and was unlawful. The system has now been suspended.

Cuts to legal aid have meant that detainees have very little access to lawyers. Serco noted that “solicitor demand continues but many [detainees] are becoming more and more frustrated due to lack of funding and options available to them.” The Home Office arranges specially chartered flights for deportations to particular countries, such as Nigeria, Pakistan and Afghanistan. The self-audits reveal that people are being rounded up on the basis of their nationality, rather than their individual immigration cases.

The Harmondsworth centre manager admitted that “figures rising and falling can often be attributed to the amount of charter operations in progress by DEPMU (Detainee Estate Population Management Unit) and other pick-up operations in effect from the Home Office enforcement teams. In certain circumstances these two departments may work together to focus on a specific nationality to fill a charter which will reflect on the amount of arrivals and first night in detention and will also affect the amount of departures.”

Days after that report was written, a leaked Home Office intelligence dossier emerged which showed immigration snatch squads were targeting nationalities in specific industries, such as Nigerians working in barber shops. Rounding up people based on their nationality in order to fill a mass deportation flight to that country would amount to a collective expulsion — contrary to European laws.

After fighting for a year to keep these self-audits secret, the Home Office has shown that the system it uses to monitor companies paid to run detention centres is deeply flawed. The companies only declared a handful of failures at their centres and the Home Office does not effectively scrutinise the reports, giving the companies carte blanche to under-report issues. This leaves people in their custody vulnerable. But the arrangement is mutually beneficial to the Home Office and its contractors — the payments keep coming, and the government can turn a blind eye.

• Steven Walker is a Unicef Children’s Champion.