North Yorkshire County Council was earmarked by the government, in March, to become a unitary council, disbanding the area's seven district councils.

Harrogate Borough Council leaders said they started court proceedings on Thursday to halt the proposals.

The county council has said there is public support for the plans.

Centralising services in Northallerton would take the local out of local government Mike Gardner Harrogate Borough Council leader

However, leaders in Harrogate claimed the merger proposals were "flawed" and undemocratic.

All of the county's MPs and district councils also object to the plans.

On Wednesday Harrogate MP Phil Willis raised the issue at prime minister's questions and told Tony Blair he should either give residents a referendum or scrap plans altogether.

Mr Blair said the fact all seven of the county's MPs opposed the unitary idea was "very powerful".

Councillor Mike Gardner, leader of Harrogate Council, said he had been taking independent legal advice from leading local government barristers.

'Undemocratic and flawed'

Two other councils elsewhere in England - Congleton and Shrewsbury - have already started challenging similar proposals.

They claim local government secretary Ruth Kelly did not have the legal power to invite councils to bid for unitary status and so any following proposals are invalid.

Mr Gardner said: "This council is firmly opposed to the undemocratic and flawed proposals made by the county council.

"This is not the right kind of local government for the Harrogate district. Centralising services in Northallerton would take the local out of local government."

'Significant savings'

But Richard Flinton, assistant chief executive of North Yorkshire County Council, rejected claims that a new unitary council would be remote.

He said: "Under a unitary council, decisions on local issues would still be made locally by strong local committees.

"By cutting through unnecessary red tape and eliminating duplication of work, we will also be able to make significant savings, keep council tax down and re-invest this money into making our already excellent services better.