Concern has been expressed over the number of freed prisoners being returned to custody in Scotland.
The early release system has come under fire
Figures have shown that returns remained at an "historically high level" in 2004, with 180 released inmates ending up back in prison.
Chairman of the Parole Board for Scotland, Professor James McManus, said it showed the system was working.
But the Tories said the "appalling" automatic early release system was putting public safety at risk.
The parole board's annual report shows the 180 returns comprised 154 non-parole prisoners released on licence, and 26 parole licensees.
Some of those recalled were subsequently re-released, but a total of 117 remained behind bars.
Prof McManus described the numbers as an "historically high level".
But he said: "The main conclusion about this level of recalls is that improvements in supervision in the community and reporting arrangement have improved and are being brought to the attention of the board so that consideration can be given to recalling the licence.
"As the recall statistics show, it is not necessary that a licensee re-offends before being recalled to custody.
"Indeed, the ideal situation is that recall should be considered before any offence is perpetrated, when it is clear that the level of risk presented has become unacceptable."
The parole board's report shows that 703 cases were considered by the board in 2004, down from 706 in 2003.
The number of prisoners released on parole fell to 311, compared to 345 the previous year.
And the number of life prisoners released on licence for the first time fell sharply, from 51 in 2003 to 28.
Prof McManus said this fall was a consequence of the clearing of a previous backlog.
Legal changes to the way life prisoners are sentenced took effect in 2001.
The system then had to catch up with a backlog of prisoners serving life who were sentenced before 2001 and had already served long sentences.
Prof McManus said: "Now that this backlog has been dealt with, it is anticipated that the numbers released each year will remain at a level closer to that in 2004."
Justice Minister Cathy Jamieson welcomed the figures and urged the parole board to ensure that public safety remained their guiding principle.
She also urged the board to give due weight to the opinion of victims, who are now entitled by law to comment on the possible release of offenders.
But Conservative justice spokeswoman Annabel Goldie said: "Two hundred and one people who were on automatic early release were referred back to the justice system for committing further crimes.
"That is more than double the number since 1998 and is utterly unacceptable.
"Four years should mean four years, not two, and 12 years should mean 12 years and not eight. Sometimes life must also mean life."