An independent review of the Criminal Records Bureau (CRB) has concluded its systems are unable to cope with the levels of demand they will face.
And the Home Office has said it does not know much it will cost to fix them.
Set up to vet applicants for jobs involving work with young children or the vulnerable, the system should be able to carry out a 'basic', 'standard' or 'enhanced' check on a candidate's background within three weeks.
Currently the CRB system is only able to offer 'standard' and 'enhanced' disclosures, and the typical turnaround time is six weeks.
Plans to bring the system up to scratch have been mothballed, and the Home Office cannot detail either the current or future costs of the project.
Delays have plagued the project. In September last year, schools across the country faced staff shortages as checks had not been processed in time.
Care homes for the elderly were hit by the delays, and hospitals' recruitment of paediatric staff was held up.
The Independent Review Team (IRT) set up to analyse the implementation by IT services firm Capita concluded that the CRB systems would be unable "to cope with the significantly higher levels of demand" included in the original business plans.
Patrick Carter, chairman of the IRT, explained that this means that plans to offer 'basic' checks "should be postponed".
This view was accepted by the Home Office, but a spokesman confirmed that, while the intention to meet the three-week target remained, "no timetable has been set to achieve it".
Each time a check is requested, the employer is charged £12. It was envisaged that the number of basic disclosures made would enable the system to be self-financing "after five years", according to Lord Falconer, Home Office minister responsible for the CRB systems.
With these plans now shelved, it is unclear when the project will recoup any of the millions of pounds spent on it so far.
Lord Falconer said that he could not provide details of what had been spent so far, because the funding came from a number of government departments.
The contract with Capita to set up and run the service is worth £400m over 10 years.
Lord Falconer would not reveal what fines had been levied on Capita for failing to deliver the service, because it was "sensitive commercial information".
The government now plans to renegotiate with Capita to provide a more sophisticated system.
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