She added: “The majority of those subject to active Mappa management do not seriously re-offend due to robust and effective management.

“Since the introduction of Mappa eight years ago, other countries around the world view the arrangements as an important development in enhancing public protection against dangerous offenders in the community.”

But Alan Duncan, the Tory justice spokesman, claimed there had been increases in both the number of serious further offences committed by the most severe offenders and the number returned to prison.

And he added: “Yet again, the Government has failed to publish any data about lower level offenders, when we have good reason to believe they may commit more serious further offences than any other group.”

Last night's Panorama programme explored that controversy, revealing at least 125 re-offences that were excluded from yesterday's official Government figures.

They were offences suspected of being committed by sexual and violent criminals placed in the lowest tier – level one – who receive far less strict supervision.

Harry Fletcher, of the National Association of Probation Officers, blamed a lack of resources, saying: “Frankly, there aren't enough police officers or probation officers to cover the cases that we've got.”