An influential group of MPs has launched a scathing attack against the head of Britain's tax office for her "catastrophic leadership failure" when she was in charge of the country's border controls.
The Home Affairs select committee said it was "astounded" that Lin Homer was promoted to the £180,000-a-year role of chief executive of HM Revenue & Customs after her performance during the five years she spent at the top of the UK Border Agency (UKBA).
But Homer said it was "unfair" to blame her for matters that occurred after she left the Agency.
The case against Homer's current appointment was made as the committee warned that at the current rate of progress it would take 24 years to clear through a backlog the size of the population of Iceland of asylum and immigration cases at the UKBA.
The report said: "It is shocking that after five years under Lin Homer's leadership an organisation that was described at the beginning of the period as being 'not fit for purpose' should have improved its performance so little.
"Given this background, we are astounded that Ms Homer has been promoted to become chief executive and permanent secretary at Her Majesty's Revenue and Customs and can therefore have little confidence in her ability to lead HMRC at what is a challenging time for that organisation."
The current UKBA chief executive - Rob Whiteman - is also criticised for failing to inform the committee that the Agency had supplied parliament with incorrect information since 2006.
The report said: "This in our view is unacceptable and undermines Mr Whiteman's claims to take the provision of accurate information to the committee seriously."
In its report into the work of the UKBA between July and September last year, the committee said four new types of backlog came to light, taking the total number of cases to 312,726.
The committee concludes that for six years the UKBA "repeatedly supplied it with incorrect information" about the size of the asylum backlog and the checks being carried out to try and trace applicants in the controlled archives.
Its report said Homer "continues to try and evade responsibility for her failings" and calls for a stronger role for Parliament when civil servants are being scrutinised for senior positions.
It added: "The status quo, in which catastrophic leadership failure is no obstacle to promotion, is totally unacceptable. We recommend that in future any failures of this nature should have serious consequences for the individual's career."
Homer became director general for the Immigration and Nationality Directorate in August 2005, which was reformed as the Border and Immigration Agency in 2008. She was the UKBA's first chief executive.
She was appointed head of HMRC, which is tasked with collecting the country's tax revenues, in January last year.
She has already written to the committee in response to their allegations, as much of the difficulties described in its
report came some 18 months after her departure.
She said: "It is therefore wholly inaccurate and unfair to seek to ascribe responsibility to me for matters of concern that occurred long after I left the Agency."
The HMRC said under Homer's leadership, the department is likely to beat targets by more than £1 billion and has improved the rate of answered calls from 66% to 90%.
Exchequer Secretary to the Treasury David Gauke said: "Under Lin Homer's leadership, HMRC has built on the good work already going on in the department, becoming increasingly effective at tackling evasion and avoidance, improving its customer service and delivering substantial efficiencies. She is a highly effective chief executive and the right person to lead HMRC."
The number of UKBA backlog cases fell by 1% quarter-on-quarter, the committee said, despite 96,000 cases closed.
The MPs said they found UKBA's progress in dealing with the backlogs is "far too slow".
Committee chair Keith Vaz MP said: "No sooner is one backlog closed, than four more are discovered. At this rate it will take 24 years to clear the backlog which still stands at the size of the population of Iceland."
The committee recommends that senior UKBA staff are not paid bonuses until there is evidence that the backlog is being "substantially" reduced and new backlogs are not emerging.
Immigration Minister Mark Harper said: "We have always been clear that the UK Border Agency was a troubled organisation with a poor record of delivery.
"Turning it around will take time but I am determined to provide the public with an immigration system they can have confidence in."