The government is "irresponsible" to expect parliament to rubber stamp its "undeveloped" reforms to educate young offenders in multi-million pound secure colleges, a former chief inspector of prisons has warned.

Lord Ramsbotham, who sits as a crossbencher in the House of Lords, told peers that he supported the government's desire to improve education for youngsters in custody, but was critical of the lack of information about the new regime.

He said the government could either "charge ahead in haste" and commit a "vast amount of public money to an untried vision" or call a halt to the secure college proposal.

In February, Justice Secretary Chris Grayling launched a green paper on setting up "secure colleges" to house and provide teaching for young offenders in custody.

At the moment young offenders are sent to either a secure training centre or a young offenders institution, depending on their age and offences.

They currently spend an average of 12 hours a week in education while in detention - but the new college would double that.

An £85m secure college to house up to 320 young offenders aged between 12 and 17 in Leicestershire is lined up to open by 2017.

Speaking during the committee stage of the Criminal Justice and Courts Bill on 23 July 2014, Lord Ramsbotham said the government had not presented evidence that it has "tested or costed" its plans for secure colleges.

"I submit that the secure college proposal is so undeveloped that it is both unreasonable and irresponsible of government to expect parliament to rubber stamp it until it knows more," he said. He added that he would not be happy to have launched a proposal on "such flimsy evidence."

Lord Ramsbotham's comments drew praise from across the House.

The Bishop of Bristol, Michael Hill, who is Bishop to Prisons, said that while he supported the government's intention he found it "difficult" to support the actual project.

"The difficulty is, for some of us, what we have at the moment enables us not to see the detail of how that might be provided."

Meanwhile, senior Conservative peer Lord Cormack said that he had been "very much persuaded" by Lord Ramsbotham's criticisms.

He told peers that very few people were able to "speak with the authority" of Lord Ramsbotham on subjects like this, adding: "If he has come to this conclusion then it behoves government and others to think again very, very carefully."

Responding to the comments, Justice Minister Lord Faulks said the government had "an open mind" about its bid to reform youth custody.

He added: "The truth is that no current model of youth custody is delivering at the moment the outcomes we all want to see, nor providing sufficient value for the taxpayer.

"It's for this reason that we are introducing secure colleges which we think will foster a culture of educational development and provide enhanced rehabilitative services while also achieving savings."