More than half of prisoners freed after serving controversial indeterminate sentences for public protection are being sent back to jail for breaching licence conditions, MPs have been told.

Giving the figures in Parliament, Nick Hardwick, chairman of the Parole Board for England and Wales, said the matter had now become a “critical” issue. In the last year, 760 IPP inmates were recalled – up 22% from the year before. Monitoring of those released had been “lacking”, the prisons minister said.

What Are IPP Sentences?

Introduced by Labour in 2005, they were designed to ensure that dangerous offenders remained locked up until it was safe for them to be let out. Under the system, prisoners were given a minimum term – or tariff – which they would have to serve before the Parole Board then decided whether to free them on licence.

However, hundreds of inmates found themselves locked up for years beyond the end of their tariff after finding it hard to access rehabilitation courses in custody in order to demonstrate they no longer posed a risk.

Courts were banned from imposing IPPs in 2012. However, 3,300 IPP prisoners remain in custody, 51% of whom are more than five years over the end of their tariff. The Parole Board and the Ministry of Justice have taken measures to ensure IPP offenders can access courses more easily and are better prepared for their parole hearings.

Sam Gyimah, the prisons and probation minister, defended the recall system, saying it struck the “right balance” and prisoners would be sent back if the nature of the licence breach directly related to the risk they posed and their original offending. “These people are incredibly risky,” he said.

The minister said in future more IPP prisoners would be electronically tagged on release to ensure they comply with the terms of their licence and there would be other “innovations” to improve their management in the community. “I put my hand up – that was lacking initially,” he said.

Asked whether the government would consider new legislation to re-sentence IPP prisoners or take other legal steps to speed up the process of their release, Mr Gyimah said “all options are under review”.

However, he gave a clear indication that it was unlikely to happen, adding: “The system is working.”

The committee also heard that the Parole Board expects to pay prisoners a million pounds in compensation this financial year for delays in hearings and decisions.

In 2016-17, 578 prisoners received a total of £938,000, which was almost double the figure the previous year.