Councillors are putting party political interests above the needs of communities and risk creating “chaos” in the biggest local government shake-up for 50 years, according to a council leader.

Devon County Council leader Julian Brazil, Liberal Democrat, accused rival councils of “gerrymandering” – manipulating boundaries for their own political benefit.

Local authorities are drawing up plans for where new boundaries should fall as the county is carved up into unitary authorities.

Councils in Exeter, Plymouth and Torbay deny seeking any political advantage and said having their own unitary authorities with a fourth authority for the rest of Devon is the best option for residents.

Currently Devon County Council governs the largest geographical area of the county in a two-tier system where it is in charge of issues such as highways and social care.

Eight district councils, including Exeter City Council, look after services like recycling and housing.

In Plymouth and Torbay, all council services are run by unitary authorities that are already in place – Plymouth City Council and Torbay Council.

Exeter City Council wants to expand to take in areas such as Crediton, Dawlish and Exmouth and become a unitary authority.

Brazil said: “It’s very unfortunate that some have seen the whole process as an opportunity for gerrymandering.”

The government indicated it wants any unitary authorities to have a population of about 500,000, but has said there could be some flexibility around that figure.

Brazil said: “Other councils have chosen to put their party-political interests first. There is a danger that we will be left with chaos.

“Many of our rural parishes fear they will become cash cows for our inner cities.”

The county council leader said they were making improvements in areas such as children’s services and it would be “a tragedy” if those improvements were disrupted by “breaking up” services.

Brazil wants to see a new One Devon unitary authority covering the same geographical area that is covered by the county council, with the continuation of unitary authorities in Plymouth and Torbay.

Phil Bialyk, the Labour leader of Exeter City Council, said Devon needed four unitary authorities after local government reorganisation.

He said there was no political gain for Labour in the expansion of Exeter.

“I’m not throwing mud at anybody about any of this and they need to look at themselves before they start throwing mud in my direction or Plymouth or Torbay’s direction,” he said.

Bialyk was critical of Devon County Council’s record on issues such as local transport, pothole repairs and adult and social care services.

“We strongly believe that things can be done better in a more localised way,” he said.

He said there were improvements needed in Exeter in areas such as traffic and said the city would be better able to deal with problems “without the heavy hand” of the county council.

Plymouth, which is also Labour-run, is backing the same solution as Exeter.

Conservative-run Torbay is also backing four unitaries with an expanded Plymouth and Exeter but wantst to keep its own boundaries as they are now.

The district councils want to see three unitary authorities in a plan known as 4-5-1.

All of the local authorities need to submit plans to government by 28 November with a decision expected in spring 2026.