According to an internal announcement, informing staff of Owen’s departure, HMRC will shortly announce an interim head of customer services and will begin recruitment for a new director general soon.

Owen joined HMRC in 2012 as director general of personal tax before being made head of customer service in October 2016 as part of the major structural reorganisation at HMRC which saw Jim Harra replace Edward Troup as tax assurance commissioner.

Before joining the tax authority Owen was work services director and deputy chief operating officer at the Department for Work and Pensions (DWP) staying in the role for only a year.

Owen has said that it was a ‘difficult’ decision to leave but adds that she has ‘a one-off opportunity to try a different career in the private sector.’

Owen said: ‘I have loved my time in HMRC and I leave feeling immensely proud of what we have achieved. The last five years have seen some significant changes in the service we provide to our customers, the way we think about our customers as well as how we do business and how we work together.

‘I know I will greatly miss so many fantastic people and teams, who I’ve been privileged to work with over the last five years. All our achievements are down to the passion, commitment and hard work of Team HMRC and our shared desire to make a difference.’

She went on to praise her former and current boss saying: 'I have particularly enjoyed working under both Lin [Homer] and Jon’s [Thompson] leadership. I feel really optimistic and confident in HMRC’s future and wish Jon and my ExCom colleagues well in steering the department towards our vision.'

Jon Thompson, chief executive, said: ‘Ruth will be hard to replace; her energy and dedication to brilliant customer services is an inspiration. Ruth’s experience and insight will be missed around the ExCom table and her drive for ever greater performance will be missed in customer services, but I wish her well as she embarks on a new career in the private sector.’