Lin Homer leaves a “legacy of which she can be rightly proud”, according to Chancellor George Osborne, as the search for her successor begins.

Ms Homer, whose public service career spans 36 years, has just been made a dame in the New Year’s Honours list.

The award was given despite significant scrutiny of HMRC’s performance under her leadership and criticism about her previous tenure as head of the UK Border Agency, which no longer exists.

Ms Homer said she was not currently actively seeking her next role and intends to take a break over the summer.

She said: “After ten years as a Chief Executive and Permanent Secretary in the Civil Service, the start of the next Spending Review period seemed to be a sensible time to move on.

“HMRC has secured Ministerial support and funding for our ambitious transformation programme and it has the leadership team in place to deliver it. My successor will be able to put their full weight behind seeing the transformation through to 2020.”

Mr Osborne said: “Lin Homer has made a real contribution to public service modernisation and transformation.”

Among her key achievements, HMRC said, was the reduction of the tax gap and tax credits error and fraud, both to record lows and recovery in customer service from a low-point of 48% calls answered in 2011, to almost 90% calls answered in December 2015, with a queuing time of six minutes.

Mr Osborne said: “She has put the foundations in place that will see HMRC become one of the most digitally-advanced tax authorities in the world.

“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.”

Sir Jeremy Heywood, cabinet secretary and head of the civil service, said: “Following a succession of challenging and important roles in a long and varied public sector career, Lin has led HM Revenue and Customs for the last four years with great distinction.

“She not only leaves behind a significantly more effective and efficient organisation, delivering more for less; she has also helped to transform HMRC into one of the most open, digitally-advanced revenue services in the world.”

He added she was a “dedicated, professional and courageous colleague and a pleasure to work with”.