Barbara Young said "Having overseen the major task of creating a single regulator for health and social care and pointed it in the right direction, I have decided that it will be for others to take it forward.  I wish all success to the Commission and its staff and to Dame Jo Williams who has agreed to act as Chairman until a successor is appointed.  Jo will start to take up the reins in January."

Cynthia Bower, chief executive of CQC, said: "Barbara joined CQC in May 2008 and her strong leadership has seen us successfully through the transition from three predecessor organisations. She has put CQC on the map as the regulator of health and social care and will be a tough act to follow. We wish her all the best in the next stage of her career."

Jo Williams, deputy chair of CQC, said: "CQC's board were sad to hear that Barbara has decided to move on, both on a professional and personal level. Barbara has played a major role in forging CQC's strategy for the next five years. The Board is fully signed up to take this strategy forward and our focus now is building on the momentum we have and delivering our important work on registration