The asylum seekers are being held because American airlines refuse to risk incurring fines by allowing them to board their planes with false papers.
Last year more than 800 of these traded refugees were jailed compared with fewer than a dozen four years ago. They are being charged with possession of false travel documents and sentenced to an average of three months in prison.
The trend, which is being linked with the 1995 introduction of carriers' liability legislation that means airlines are fined for carrying illegal immigrants, is revealed in a report today by the National Association of Probation Officers.
Some of those arrested were jailed for nine months, at a cost to the British taxpayer of about pounds 20,000.
Harry Fletcher, the association's assistant general secretary, said: "Virtually all of them come from authoritarian countries, and the experience of British jails traumatises them further. It seems inhuman and a waste of taxpayers' money to prosecute these people."
Most of the traded refugees - who are flown back to their country of origin after being released from jail in Britain - come from Iraq, Iran and Algeria.
They are among a record 4,664 foreign nationals being held in British jails. The numbers have grown by 44 per cent over the past 12 years, a rate that surpasses even the exceptional growth in the incarceration of British nationals.
The association said that, although 1,000 of these prisoners were eligible for repatriation to their country of origin, only 17 were transferred last year.
The report, Foreign Nationals in British Jails, also finds significant anecdotal evidence that black foreign prisoners, particularly women jailed for drug offences, are given much harsher sentences than white foreign nationals who have committed similar offences.
The report contrasts a series of female Caribbean cocaine smugglers, who are serving sentences of 10 years or more, with a French woman who received four years for importing 10 kilograms of the drug.
Mr Fletcher said: "Everyone that works in the system says that black foreigners get higher sentences than Europeans. Many foreign nationals in UK jails also had poor access to lawyers and translators, and were given little information about appeal procedures."Reuse content