The Ofgem board will initiate a formal search process to appoint a permanent successor, but in the interim, Tim Jarvis, currently the Director General for Markets, will serve as Acting CEO.
Jonathan Brearley said: “It has been a privilege to lead Ofgem and work alongside such a talented group of public servants. I am proud of all that we have achieved together.
“I am confident that Ofgem is in excellent hands with Tim alongside the wider executive committee and well-positioned to continue delivering on its mission to protect energy consumers now and into the future, as we advance through the energy transition.”