Thousands of foreign prisoners due for deportation have been released into the community without being tagged, Theresa May has admitted, leaving the door wide open for their abscondment. In a letter sent while she was Home Secretary, Mrs May admitted that fewer than one in ten were being monitored.

The letter, sent last month to Keith Vaz, chair of the Home Affairs Select Committee while Mrs May was still Home Secretary, revealed that all of the offenders were “subject to ongoing deportation action.” Mrs May added: “We do not give up trying to deport these individuals.”

However, she confirmed that just 493 out of 5,789 “foreign national offenders” released from prisons into the community had been issued with “radio-frequency tags” to enable police to monitor them, the Telegraph has reported.

In 2007 the government was forced to hand out compensation to foreign prisoners who were held beyond the end of their sentence while deportation orders were considered. Consequently the authorities now release the prisoners back into the community to await deportation proceeds.

But the pace of deportations is currently laboriously slow, with as few as 102 foreign nationals being deported over the 16 months between February 2015 and June 2016, down from a peak rate of 5,613 in 2008/09. There are currently around 10,000 foreign national prisoners in British jails.

Mrs May said she hoped the rate would improve “as new practices and procedures become established across Europe”.

The figures hark back to a 2006 scandal in which it emerged that 1,013 foreign national prisoners had been released into the community without efforts made to keep tabs on them. The scale of outcry over that revelation caused the then Home Secretary Charles Clarke to lose his job.

But in her letter, Mrs May admitted that ten years on, 26 of the original 1,013 foreign offenders were still unaccounted for.

Mr Vaz said: “The utter failure to improve the management and removal of foreign national offenders has been lamentable.

“Despite firm commitments to improve, and a massive ten-fold increase in resources, the system appears to be totally dysfunctional.

“It is simply unacceptable that our allies in Europe and elsewhere are seemingly obstructing the transfer of their citizens, who have committed serious offences, back to their own countries.

“Regardless of Brexit, until the UK leaves the EU, the commitments made by Member-states must be honoured.

He added that with fewer than 10 percent of offenders tagged, there was a “clear risk of absconding.

“Given that 26 of the foreign national offenders who went missing when Charles Clarke was Home Secretary are still missing, one can only fear that the Home Office has not learnt any lessons from its past failures,” he concluded.

In January last year, the Committee of Public Accounts found that close to £1 billion had been spend on thousands of foreign criminals in the UK in the year between April 2013 and March 2015.

It noted findings by the National Audit Office that One in six – or 760 out of 4,200 – foreign national offenders (FNOs) living in the community had absconded. The figure included 58 ”high harm” individuals missing since 2010.

It was also revealed that the Home Office had been forced to pay out £6.2 million in compensation payments to 229 foreign national offenders, thanks to delays in dealing with cases since April 2012. The offenders were handed an average of £27,000 each.