Averil Dongworth has said her three years at the trust behind King George Hospital and Queen’s Hospital have been the “most challenging” of her career.

She is retiring as chief executive of Barking, Havering and Redbridge University Hospitals NHS Trust (BHRUT) at the end of the month.

It comes just weeks after the shock resignation of trust chairman Sir Peter Dixon.

Ms Dongworth had planned her retirement before the trust was put into special measures following a damning CQC report in December.

The status is imposed by the NHS when trust managers are not considered capable of resolving systematic failings.

The NHS Trust Development Authority has appointed an improvement director to oversee a plan to bring services up to standard and the results of a review of senior management have not yet been announced.

Ms Dongworth said: “I am proud that the Trust has made great strides since the hospital-wide CQC investigation in 2011.

“I believe the trust is now in a much stronger position with a real opportunity to build for the future, so that the people of Barking and Dagenham, Havering and Redbridge will have healthcare services they can rely on and be proud of.”

She thanked fellow executives, hospital staff and partners for their support.

Interim chairman of BHRUT, Dr Maureen Dalziel, said: “We are extremely grateful for the dedicated leadership and for the huge contribution Averil has made to the trust.”

A trust spokesman said Ms Dongworth had been in the NHS for 40 years and is looking forward to spending time with her family and friends and pursuing her own projects in health and conservation.

The new chief executive, who has not yet been appointed, faces heading one of the busiest and most overcrowded hospitals in the UK as well as taking on the trust’s huge financial problems.

Board papers last month revealed the deficit at the end of December expected to reach between £27million and £33m.

The A&E at King George Hospital, Goodmayes, which has historically performed much better than Queen’s, is due to be shut in 2015 as part of a huge reconfiguration of services at both hospitals.