The chief executive of South East Coast Ambulance Service Foundation Trust - the subject of major concerns over delaying responses to some calls - has left the trust after 10 weeks’ absence.

Paul Sutton began an agreed leave of absence in mid March on the publication of a critical report into a controversial pilot project at the trust, under which it decided to delay its ambulance response to some calls. The chair of the trust left at the same point, and Monitor installed Sir Peter Dixon as interim chair.

The trust said this morning that Mr Sutton had left the organisation. It refused to say on what terms he had left.

In a statement it said: ”The trust would like to thank Paul for his contribution to the developments and achievements of the trust over the past 10 years. The process for finding a permanent replacement will start immediately and will be subject to further announcements as appropriate. In the interim period, Geraint Davies [previously director of commissioning at the trust] will continue as acting chief executive.”

The trust ran the controversial scheme for a period of months at the end of 2014 and into 2015, during which some patients calling NHS 111 but judged to need an eight minute ambulance response were “retriaged” and the ambulance despatch delayed by up to 10 minutes.

The pilot scheme – of which many board members had scant knowledge and was only revealed after commissioners raised concerns – led to Monitor intervening at the trust and ordering a number of reports.

The first of these was published in March and said the chief executive “made the ultimate decision to proceed with the pilot and played a critical leadership role throughout”. It revealed that concerns were raised with the chief executive over the scheme and he instructed the pilot should go ahead. It was also highly critical of the board’s governance.

Mr Sutton had been chief executive of the service since 2006 and before that had been chief executive of the Sussex Ambulance Service. He is a qualified paramedic.