Delays and overspend in the delivery of an offender tracking database were the result of over-optimism and lack of accountability in Whitehall, according to a report from the Public Accounts Committee this week.

The system was designed to track offenders as they passed through the prison and probation system.

The C-Nomis project, run by the National Offender Management Service (Noms), has doubled in cost to £513m and is expected to be delivered over three years late.

Edward Leigh, chairman of the Public Accounts Committee, said his committee was surprised by the extent of the failure.

"This project has been a shambles. We now expect the substantial progress in its implementation promised by Noms to be demonstrated satisfactorily to a future hearing of the committee," he said.

The project has a chequered history. In 2003, the Correctional Services Review recommended bringing together prisons and probation services and introducing "end-to-end offender management".

This was designed to improve the supervision of individual offenders throughout their sentence by a single offender manager, whether that sentence was served in prison or in the community.

The committee says the original vision was achievable but costs soon spiralled.

Senior managers were inexperienced and oversaw a culture of poor planning, poor financial monitoring, inadequate supplier management and too little control over changes, according to the report.

The lack of a dedicated financial team meant that costs and progress were not monitored or reported for the first three years of the programme. The Home Office and ministers were thus unaware of the true cost and lack of progress until 2007.

In 2007 rollout of the system was halted because new analysis showed costs had trebled. The programme was revised and scaled back to three offender databases - each recording different information about an offender and with limited data sharing between them.

The report said that this undermines the original concept of the scheme - an end-to-end record for a person passing through the prison and probation services - and recommends that Noms test the data-sharing functionality extensively after the project is finished.

"It is essential that the programme is developed with data sharing enhancements in mind," it says.

Noms has assured the committee that it has implemented the changes needed to deliver the revised project by 2011.

But the report points out that there are significant challenges still to address to ensure successful delivery, including further contract negotiations with suppliers.

"We look to Noms to implement the new systems effectively and deliver the intended benefits," it says.