HOME OFFICE ministers privately sanctioned a change in policy to allow the early transfer of hundreds of dangerous criminals, including foreign convicts, to open prisons despite the risk that they would abscond.

Tony McNulty, the beleaguered minister at the centre of the foreign convict scandal, admitted in a letter that overcrowding in secure prisons had led to “open prisons being asked to take prisoners who would perhaps have not previously been allocated there”.

McNulty was last week stripped of his responsibility for immigration and switched to handling police affairs.

Prison governors also revealed this weekend that they had come under “inappropriate pressure” from Home Office officials to send prisoners to open jails, even though they were judged likely to escape.

Those who subsequently absconded have been responsible for a series of crimes — including violent robberies, sexual assaults and false imprisonment.

The shift in practice by the Home Office has never previously been publicised and only came to light after last week’s disclosure that hundreds of prisoners — among them, murderers, rapists and robbers — have absconded from open prisons.

On Friday, it emerged that 11 foreign prisoners facing deportation at the end of their sentences are also missing after walking out of Ford open jail this month.

At least 741 foreign prisoners have been moved to open prisons, as part of the Home Office’s relaxation of the rules determining which criminals are sent to open prisons to ease overcrowding. Internal Prison Service documents show that in July 2002, Brodie Clark, the service’s director of security wrote to all prison governors advising them about the new policy.

The memo, entitled “allocation of deportees to open conditions”, states: “This policy change removes the blanket ban on the categorisation and allocation to open conditions of prisoners subject to enforcement under the Immigration Act.”

The policy has remained, in the face of warnings to the home secretary by the official inspector of prisons that the number of absconders, running at 1,000 a year, is increasing because of the number of “less suitable” prisoners being transferred to open prisons.

One former governor of an open prison said he and other governors had faced Home Office pressure to ease overcrowding by routinely “slipping” inappropriate prisoners into a lower security category so they could be sent to open prisons. “There’s been manipulation of the system,” he said.

Another serving governor disclosed how they were telephoned every week by Whitehall mandarins and given specific orders for the number of prisoners to be moved into open prisons such as Ford and Leyhill. A third governor at an open prison told his MP that he was being prevented from sending dangerous criminals back to secure accommodation.

The number of escapes has risen by about 25% since the Home Office began sending “unsuitable prisoners” to open jails three years ago. About 2,000 criminals who have absconded are still understood to be at large.

In a letter to Steve Webb, the Liberal-Democrat MP for Northavon in Gloucestershire, which covers Leyhill open prison, signed by McNulty on behalf of Fiona Mactaggart, the prisons minister at the time, the ministers outline the “policy of placing prisoners in open conditions”. The letter goes on to acknowledge that “more robust” assessment procedures are necessary.

The prison system is facing an unprecedented level of overcrowding as Labour refuses to fund new prisons — a policy promoted by the Conservatives. This autumn, the system is expected to reach breaking point when the prisoner population hits 80,000.

David Davis, the shadow home secretary, said the McNulty letter showed how the Home Office had compromised its public commitment to protect the safety of the public.