The official prisons watchdog has expressed ‘substantial concerns’ about Europe’s biggest immigration removal centre (IRC) following an unannounced inspection.

Peter Clarke, Chief Inspector of Prisons, also called for a time limit to be placed on how long someone can be imprisoned for under immigration powers.

In today’s new report into Harmondsworth IRC, based near Heathrow airport, the prisons inspector slammed the facility for locking some people up for an ‘unreasonably long time’.

Inspectors discovered that 18 detainees had been held for more than a year and three for more than two years. These figures did not capture detainees who had been released and then re-detained. For example, one detainee had been detained on separate occasions for a total of five years, and another for almost four and half years.

As a result, the Chief Inspector echoed growing calls for a time limit to be placed on how long someone can be detained for.

He also criticised the ‘appalling’ conditions inside the detention centre, citing concerns about overcrowding and calling the toilets and showers ‘seriously insanitary’.

The inspection condemned the continued detention of detainees against the advice of medical professionals’ advice, and revealed that detainees without a lawyer often had to wait nearly two weeks to see one.

Worryingly, inspectors also uncovered poor handling of cases where detainees claimed to be children: in one instance, instead of sending the young person for a full, lawful age assessment by social services, unqualified Home Office staff made a judgement on the person’s age.

The Refugee Council knows all too well that such casual assessments can lead to many children being wrongly and often unlawfully locked up alongside adults. Peter Clarke called for all detainees who say they are children to undergo a Merton-compliant age assessment by social services.

Refugee Council Head of Advocacy Dr Lisa Doyle: “The evidence against the Government’s current policy of callous, casual, indefinite imprisonment is mounting.

“The very idea that Britain locks up people who have fled here seeking safety should be a stain on the Government’s conscience, but the fact that Home Office officials are then able to throw away the key is utterly scandalous.

“If the Government is insistent on continuing this ruinous policy, it at the very least must put a time limit on the length of time it throws people behind bars for.”