The leader of West Norfolk Council, Nick Daubney, has announced he will step down from the post in the spring.
In a surprise move, Mr Daubney, who has led the authority for the past nine years, will leave the role in May.
And his deputy, Alistair Beales, has already ruled himself out of the running to replace him.
Mr Daubney revealed today that he had been considering his future before last May’s elections, which saw the Conservatives increase their majority on the council.
But he said he felt now was the right time to step aside to enable his successor to shape the future of the borough within the changes expected to be brought about by regional devolution proposals.
He said: “I’m treating this as a very positive step. I think the council is in a good place but it’s going to face huge challenges and changes, as are all councils.”
First elected to the council in 1999, Mr Daubney served as deputy leader for four years under John Dobson before taking over the top job himself in 2007.
He said: “Not everybody is going to agree, but I’m really proud of what we’ve achieved over the last few years as a council.
“I want to continue as a borough councillor. I take my ward work seriously and I want to be able to support the new leader, whoever takes over.”
However, he also revealed that a bout of ill-health last autumn had influenced his decision.
He said: “I feel healthy and I’m full of energy still, but it wouldn’t be appropriate to carry on to the next election.
“Being so ill did focus my mind a little bit on what I want to do with my future.”
One of the defining moments of his tenure as leader came in 2011 when the borough council commissioned a local poll on Norfolk County Council proposals to build an incinerator on the edge of Lynn, before working with other politicians and campaigners on the fight against it.
Mike Knights, a key figure in the campaign, praised Mr Daubney for his part in it.
He said: “I’m very glad we had a leader at a local level who was prepared to stand up for us. If we hadn’t had that, we would have just been ignored.”
North West Norfolk MP Sir Henry Bellingham also paid tribute to Mr Daubney’s “outstanding” career.
He said: “He has achieved a great deal. A lot of the regeneration that has taken place in King’s Lynn is because we have had a proactive borough council.
“We have a very good plan for the future of the borough and I think a lot of the success is due to Nick’s personal leadership. He’ll be a very hard act to follow.”
Labour group leader John Collop said: “I’m going to have clashes with him but I respect what he’s done as a leader and what he’s done for the council.”
The Conservative group will choose its new leader at its annual general meeting in April. Whoever is elected would then be expected to take over as council leader in May.
But Mr Beales, who Mr Daubney appointed as his deputy following the last elections, said he would not be putting his name forward because of work and family commitments.
He said: “Nick devotes all his time to it and does a very good job. I couldn’t do that. The more time that can be devoted to it, the better, and I’m not in a position to do that.”
However, environment portfolio holder Brian Long, who was deputy leader himself before being replaced by Mr Beales, said he was thinking of standing.
He said: “I’ll talk to my colleagues, see if I’ve got support and then give it serious consideration.
“It’s something that I feel I’ve done the apprenticeship for, but I won’t jump into it as yet.”