Immigration minister Beverley Hughes has been cleared by an internal Home Office inquiry of authorising the fast tracking of applications from immigrants from the new EU accession states.
The recently appointed minister blamed staff in her department for the secret policy, which allowed checks on eastern European immigrants to the UK to be waived.
The Home Office internal inquiry cleared ministers of allegations that they had backed the strategy in attempt to manipulate immigration figures ahead of EU expansion on May 1st.
However, the investigation by IND manager Ken Sutton highlighted a number of deficiencies in the Home Office's Immigration and Nationality Directorate (IND) and staff involved with the scheme are now facing a disciplinary investigation.
Ms Hughes said the inquiry showed staff had "gone too far" in easing checks on immigrants, but insisted that there was no suggestion that mistakes were deliberate or the result of lack of effort. "Rather there was an excess of zeal in pursuing the common objective of reducing backlogs," she claimed.
She announced that an "urgent overhaul of management and reporting processes" was under way in the IND.
Publishing the report yesterday, Ms Hughes, who faced calls to quit over the row, said systems would be tightened and the findings of the inquiry fully enforced.
The report found that the decision to introduce the secret policy was "taken by middle ranking mangers" at the IND's Sheffield office and concluded that the guidance "had nothing to do with wanting to suppress the number of people coming here from EU accession states".
Whistleblower Steve Moxon, who works for the IND, alleged in the Sunday Times earlier this month that the policy was designed to reduce immigration figures ahead of ten new countries entering the EU this summer. Mr Moxon called the report a "whitewash".