HM Revenue & Customs (HMRC) chief executive Lin Homer will step down from her post in April, the government has announced.
Ms Homer was recently made a Dame in the New Year honours list, but has recently faced stiff criticism from MPs over HMRC's "unacceptable" customer service.
In fact, the Public Accounts Committee said that HMRC was "incapable of running a satisfactory service".
Ms Homer, who will leave the job after four years, said: "It has been a privilege to have been with HMRC during a period when the improved performance of the department has been increasingly recognised and we have the full backing of ministers for our future plans."
Despite criticism from MPs, George Osborne said: "It is to Lin's great credit that the National Audit Office last year judged HMRC to be one of the strongest departments in government - a legacy of which she can be rightly proud."