An uncertain future awaits the Whittington Hospital following the shock resignation of its chief executive this week.

Dr Yi Mien Koh, who has been in charge since March 2011, announced she will be stepping down at the end of the month after taking Whittington Health, the trust that runs the hospital, “as far as she can”.

Her time at the helm has been a troubled one – including a dramatic u-turn over a plan to sell buildings at the hospital site in Magdala Avenue, Archway, known as the estates strategy, in the face of huge public outrage.

Her sudden departure – described as a “bolt from the blue” by one health boss – has led to concerns over the stability of the hospital.

Shirley Franklin, from the Defend the Whittington Hospital Coalition, said it was a sign that “all is not well at the Whittington”.

She said: “Given the fiasco with the attempted sell-off I’m not overly sympathetic to her departure.

“But I think it’s interesting she has left so soon after the appointment of chairman Steve Hitchins.

“People seem to be leaving in their droves, often with no jobs to go to.

“Whittington Health is not a happy ship at the moment.

“It’s important that whoever is chosen to replace her is someone who will consult with the community, someone who is able to stand up to the politics, and someone who will put patient care back at the heart of the Whittington.”

Dr Koh’s departure comes just weeks after Mr Hitchins publicly spoke out against previous decisions made by those in charge of the Whittington.

Mr Hitchins, a former Liberal Democrat leader of Islington Council, attacked Whittington leaders for “unnecessarily upsetting” the community over the attempted sell-off of hospital buildings last year, and even blamed lowering staff morale on “weak leadership”.

Cllr David Winskill, who sits on Haringey’s adult and health scrutiny committee, said: “I was unaware of any suggestion she was about to move on.” He described her as a “highly intelligent and open individual” who had done a great deal to support the Whittington.

Cllr Winskill added: “She has always been willing to meet and apologised for the difficulties created by the publication of the estates strategy.

“I had hoped she would continue in her role as chief executive as she was clearly very capable and absolutely dedicated to improving health outcomes in our part of north London.”

On her departure, Dr Koh said: “I have had three very happy years at Whittington Health.

“However, I feel that I have taken the trust as far as I can.

“Whittington Health needs someone to take the trust forward on its journey to become a foundation trust.

“I have had a number of approaches and I am looking forward to the challenges the opportunities may present.”

Mr Hitchins said: “I would like to thank Yi Mien for her hard work, energy and expertise in taking the organisation forward as an integrated care organisation.

“I wish her every success in the future.”

Taking over as interim chief executive is former South Tees Hospital boss Simon Pleydell, who will take charge on April 1 until a permanent successor is found.

During his tenure at South Tees, Mr Pleydell had to deal with a 4,000 strong march over closures at Friarage Hospital.

Most recently, he has been working at the NHS Confederation as an associate director leading innovation, improvement and change policy.