Foreign offenders awaiting deportation are being locked up for years after their sentences have ended in a potential breach of their human rights, the immigration watchdog has warned.
They are being held in detention, at the cost of tens of thousands of pounds to the taxpayer, because of delays in obtaining travel documents for them.
John Vine, the independent chief inspector of borders and immigration, uncovered a case of an ex-offender who remained behind bars for more than three and a half years.
His findings come nearly eight years after the exposure of chaos surrounding the treatment of foreign criminals awaiting deportation cost the Labour minister Charles Clarke his job as Home Secretary.
Mr Vine urged the Home Office to mount a fresh review of its approach to removing offenders born abroad who had destroyed their passports.
After examining a sample of 27 ex-prisoners who refused to co-operate with their removal, he found they spent an average of 17 months in immigration detention centres awaiting removal at a cost of £86,000 each.
In one instance, an offender had been held for an extra 1,288 days at a cost of £211,000.
Mr Vine said he was concerned to find they were being held for “months or even years in the hope they would eventually comply with the re-documentation process”.
He said: “Given the legal requirement only to detain individuals where there is a realistic prospect of removal, this is potentially a breach of their human rights. It is also very costly for the taxpayer.”
The Chief Inspector criticised the Home Office for obtaining thousands of emergency travel documents for people Britain wants to deport, but failing to use them.
“In some instances these agreements dated back more than ten years. Many cases were not being actively progressed, leaving individuals’ immigration status unresolved. This is unacceptable,” he said.
The Home Office said it was working to improve the use of emergency travel documents which it said played a “vital role in tackling and removing immigration offenders”.
In a separate report, Mr Vine also warned that immigration enforcement officers had routinely abused their powers when they carried out raids on businesses suspected of harbouring illegal workers.
They are often authorised by a senior manager to enter premises, such as restaurants and clothing factories, and make arrests without the need for a search warrant.
Mr Vine concluded that the officers were unjustified in using the power in 59 per cent of cases he investigated. In six raids they could even have acted unlawfully because the authorising officer was senior enough or because the power was not acted upon quickly enough.
The Home Office has also come under fire from peers who protested that immigration and visa policies are damaging Britain’s standing on the world stage.
A House of Lords committee called for students to be removed from net migration targets and for a change in tone from the government in its language about immigration.
It said: “The Government must present and communicate their visa and immigration policies with a level of balance and in a tone that do not discourage those who would add to the UK’s prosperity from coming to the UK and supporting its businesses. We do not believe that this is always the case at present.”