The figures were released as the justice secretary, Jack Straw, announced a new package of reforms aimed at cutting prisoner numbers and confirmed he would press ahead with the construction of three "Titan" jails to create 7,500 extra prison places by 2014.

Prisoners on the early release scheme committed 301 crimes between its introduction last June and December.

Of those released, 215 have reoffended and 117 are on the run after defying orders to return to jail.

If the same rate of release is maintained over the next six months, it will mean 31,000 criminals will have been freed in the scheme's first year. When it was launched, ministers said the annual figure would be 25,000.

The end of the custody licence scheme creates a presumption that prisoners serving between four weeks and four years will be released 18 days before their sentences end.

The shadow justice secretary, Nick Herbert, said early release had "put the public at risk" but failed to deal with prison overcrowding, which he blamed on a refusal to build more jails.

The government had created "more than 300 unnecessary victims of crime", he said. "They should have been protected by the criminal justice system but have been let down by Labour's incompetence

"This early release scheme must be scrapped immediately and sufficient prison places provided so that public safety comes first."

Reforms announced by Straw today include involving more employers in training offenders and giving them jobs, drug treatment programmes in jails, and cracking down on the drugs trade in prisons. Four more drug courts will be created, along the lines of pilots in west London and Leeds.

Straw said he was embarking on "a major drive to overcome some of the barriers to the rehabilitation of offenders".

He had suggested yesterday that the "Titan" jails might not go ahead, but Gordon Brown later insisted they would be built after consultation.

The Liberal Democrat justice spokesman, David Heath, condemned ministers for "desperately trying to convince themselves they can simply build their way out of this crisis".

"If the government really wants to reduce the number of people in prison it should focus its attention on increasing secure mental health provision and drug treatment places," he said.

Jackie Worrall of the crime reduction charity Nacro said the initiatives were "certainly not new".

"Opportunities for tackling drug addiction and making links with employers on the outside have existed for some time, but long-term overcrowding has severely hampered access to the programmes," she said.