Britain's immigration system is "fitter than it was" after a shake-up in the way it works, the head of the border and immigration agency has told MPs.
Lin Homer said more foreign prisoners were being deported and it had cleared 17,000 of a 52,000 case backlog.
But she told a select committee more needed to be done and she gave its performance "six out of 10".
John Reid described the immigration service as "not fit for purpose" in May 2006 when he became home secretary.
Mr Reid split the Home Office in two following a string of blunders, including the release of 1,019 foreign prisoners without being considered for deportation, before standing down as home secretary last year.
Ms Homer, then head of the immigration and nationality directorate, told the home affairs committee last July it would "at least a couple of years" to get the service "into the shape I would like".
Asked on Tuesday by the same committee if she thought it was still unfit for purpose, she said: "We are fitter than we were."
But she added that it would take "a number of years to get the changes to work as smoothly as we would like".
Pressed on how she would rate her department's performance, she said: "I would be pleased if you gave me six out of 10."
She said the department deported 4,000 foreign criminals last year, compared with 2,600 in 2006.
This was down in part to an increase from £800 to £1,500 in the amount of cash offered to some foreign prisoners to return to their home countries, she told the committee.
Asked if giving money to foreign criminals was a good use of public funds, she said it was "in the interest of this country and the best use of resources".
She said progress had also been made in persuading countries such as China, which had recently signed a memorandum of understanding with the UK, and Jamaica to admit prisoners deported by Britain.
But there were still "200 to 300" foreign prisoners who had reached the end of their sentences but were locked up awaiting deportation.
"The length of time it has taken us to get close to removing them is frustrating," she added,
Countries such as Vietnam, Algeria, Eritrea, Zimbabwe and Somalia, were proving difficult to reach an agreement with.
For example, only one Somalian prisoner had been deported in the past year, out of "hundreds".
"It is very difficult to have a conversation with Somalia because there really isn't a country to have a conversation with," she told the committee.
She also confirmed that discussions were taking place over the removal of restrictions on foreign workers taking jobs that could be filled by British workers.
At the moment, firms have to carry out a test to establish whether a job could be filled by a member of the indigenous workforce before seeking employees abroad.
But under the new points based system being introduced this year, for people from outside the EU, the test could be removed for a wide range of white collar professions and trades over a certain salary level.
Challenged by Tory MP James Clappison to confirm that "tier two" restrictions would be lifted on higher earners, Ms Homer said there "ongoing discussions".