A group of MPs have criticised the former head of the UK Border Agency for her "catastrophic leadership failure", and claimed that clearing the backlog of immigrant cases could now take 24 years.

In a scathing report from the Home Affairs Select Committee, Lin Homer has been condemned for not sufficiently handling the size the asylum backlog and for refusing "to take responsibility for her failings".

The committee added they were "astounded" that Homer was promoted to the role of chief executive of HM Revenue & Customs following her "unacceptable performance" at the UKBA.

The report argued that the agency has been clearing the backlog of asylum cases far too slowly, adding that at the current rate it will not be cleared until 2037.

The report looked at the performance of the agency between July and September, and revealed the UKBA was dealing with four new types of backlog, with a total of 312,726 cases in the system - a reduction of only four percent from the previous quarter.

Committee chairman Keith Vaz said: "Successive UKBA Chief Executives have presided over chaos including 150 boxes of unopened mail, 100,000 unopened letters and yet another effective amnesty for thousands due to calamitous inefficiency.

"For six years the Committee was misled by UKBA Chiefs about the agency's unacceptable performance. It appears more like the scene of a Whitehall farce then a Government agency operating in the 21st Century.

"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.

"We were astonished to discover that MPs and applicants had been writing about cases yet 59,000 applications had not even been loaded onto the Agency's computers.

"We are worried that given UKBA's poor record of being transparent with the Committee, the delays we know about could only be the tip of the iceberg. UKBA must publish a definitive list of all its backlogs and senior staff should not receive any bonuses until the backlogs are cleared."

The report added: "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 - was also criticised in the report for failing to notify the committee that the Agency had supplied parliament with false information since 2006.

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."