The search for a candidate to take on the pounds 120,000-a-year post has already begun with the appointment of headhunters. An appointment is hoped to be made before the autumn.
The widely anticipated move follows the decision outlined in last month's utility green paper to merge Offer and Ofgas into one body following the liberalisation of the gas and electricity markets.
Ms Spottiswoode's pounds 96,000-a-year contract ends on 31 October and she had already made it plain to friends and colleagues that she did not intend to stay on either at Ofgas or as head of the combined regulator.
Professor Littlechild's pounds 109,000-a-year contract does not expire until August. He has agreed to stay on, probably until the end of the year, to ensure an orderly transition and to oversee the opening up of domestic competition in electricity.
Advertisements for the new energy regulator's job call for someone with an understanding of how government and regulation operate and who is "an excellent communicator and of unquestioned integrity".
A possible candidate is Anna Walker, former deputy director general of the telecoms regulator Oftel, now conducting the Government's energy review.
Whitehall officials stressed yesterday that Professor Littlechild's decision to leave was his own and that ministers would have liked him to stay on. Colleagues say that he may move into consultancy, perhaps for one of the big integrated US power utilities.
The person appointed will initially take over as head of Ofgas and then move into the job of combined regulator. The Government has left open the possibility of replacing the post of individual regulator with a board or commission, in which case the job will be to chair the new body.
Ms Spottiswoode's departure became inevitable after she was overruled by the Energy Minister John Battle in a dispute over the marketing of gas and electricity. She had wanted to prevent electricity companies from selling gas to customers until their own markets were open to competition.
Announcing the changes yesterday, Mr Battle was effusive in his thanks to Professor Littlechild, recording his "strong appreciation" of his contribution and the "key role" he played in improving service and lowering prices.
His comments about Ms Spottiswoode were more perfunctory.
Jeremy Warner, this pageReuse content