The resignation of Uttlesford council leader John Lodge will leave voters with "many questions", opposition councillors have claimed.
Councillor Lodge will become a backbench Uttlesford District Council member on Tuesday, December 7 for the first time since he led the Residents for Uttlesford party to victory in 2019.
He will retire as a Saffron Walden Shire ward councillor at the next election, planned for 2023.
Cllr Petrina Lees, the current deputy leader, intends to replace Cllr Lodge to become UDC's first female leader.
But councillors from the Conservative, Liberal Democrat and Green parties have called for more transparency and accountability at the district council.
They have said Cllr Lodge's premiership has been defined by "controversy".
Cllr Lodge said: "I am 76 now.
"This was planned from the start and, should I stand for another term, I would be 82 at the end of it.
"We have just appointed a new Chief Executive member of staff at the council, so we thought now was the perfect time for younger leadership."
Cllr Lodge became leader in 2019, and led the district council throughout the Covid-19 pandemic.
His administration has been criticised for spending around £2.5 million on a failed bid to prevent Stansted Airport expansion, and for its handling of the Local Plan - the set of rules used to approve or refuse planning permission in the district.
The Crown Prosecution Service received a file from Essex Police last month (November) after a "governance issue" probe at UDC.
But the administration has built up a £275 million property portfolio over the past three years, which could generate £7.5 million for the public services each year by 2023/24.
Cllr Lodge said: "I would do exactly the same things again.
"I absolutely believe in localism - we have the freedom to care for residents without pressure from Westminster parties."
He said opposing Stansted Airport's planned expansion was the right thing to do to benefit Uttlesford and to help combat the climate crisis.
Opposition councillors have questioned why Cllr Lodge has decided to resign this year.
Cllr Chris Criscione, Conservative group leader, said: "People want to know - is this anything to do with the police probe underway?
"Why all change, and why now?
"Regardless of the chaos, we are committed to conserving, protecting and enhancing our district."
Cllr Melvin Caton, Liberal Democrat group leader, said: "We welcome the news that Cllr Lodge is stepping down as leader.
"Under his leadership, the R4U administration mishandled the Stansted Airport planning case.
"R4U has failed to deliver on its pledge to build more council houses in the district than the previous Tory administration.
"I hope that his successor will be less confrontational and show a genuine desire to work with other parties on the council."
Since 2019, several R4U members have defected to the Green Party.
Cllr Vere Isham defected in May this year.
He responded to Cllr Lodge's resignation by wishing Cllr Lees luck, if she takes up the post.
Cllr Isham said: "I think it's fantastic that UDC will have a female leader.
"It's not a lie that Cllr Lodge intended to resign all along.
"But R4U has not followed due process - we found out the date through a public document and the press, when we should have been briefed.
"The R4U we have now is not the one which I joined.
"It makes me angry that the accountability, honesty and respect which residents and council officers deserve is lacking."
Council members will need to vote for the next leader on December 7.
R4U is backing Cllr Lees for leader.
Cllr Lees said: "Fixing the issues which we inherited at the council has been a huge job, and John has been outstanding in his guidance.
"The team and I thank John and our other hardworking colleagues."
A reshuffle will result in more than a dozen changes in UDC leadership, Cllr Lees said.
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