More than 80 prisoners went on the run from Leyhill prison in Gloucestershire last year, the jail from which Roddy McLean escaped. The open prison near Bristol houses about 480 inmates, all of whom should be Category D - low-risk offenders.
New figures show that 82 inmates absconded between 1 November 2002 and 24 October 2003. Of these, 19 have not yet been recaptured. The Government made the admission in reply to a parliamentary question from Steve Webb, the Liberal Democrat MP whose constituency includes Leyhill prison and who is now investigating the McLean escape.
Mr Webb said: "I asked the original question because I wanted to find out whether the pressure on the prison system, with record numbers of inmates, was resulting in Leyhill being sent prisoners who are inappropriate for open prison. I support the principle of the open prison but only low-risk prisoners should be sent to somewhere like Leyhill."
While prison escapes can be dramatic - last summer Clifford Hobbs, 43, a violent professional criminal, escaped from a prison van which was ambushed by two armed men - most inmates simply walk out of jail.
The latest figures released by the Home Office for 2002 show that the number of adult men absconding from prison is the highest since 1997. Some 647 men absconded, of whom 505 walked out of open prisons such as Leyhill. The total number of absconders from prisons in England and Wales for 2002 is 864, of which 203 were from young offenders' establishments and 14 from women's prisons. The number of women escaping has been dramatically reduced in recent years.
A spokesman for the Prison Service said: "Eighty-two absconders may seem a high number, but you have to bear in mind that up to a couple of thousand inmates might pass through Leyhill in a year."
David Blunkett, the Home Secretary, had already asked the Prison Service to report on how it could make better use of open prisons.