A LEGAL challenge that could stall or even halt the abolition of more than a dozen councils across the region is expected to be mounted in the next few days.

Government lawyers have until 4pm today to respond to a legal action brought against plans to replace the two-tier council system with unitary authorities - including "super councils" for County Durham and North Yorkshire - by April 2009.

Legal action is being brought by Shrewsbury and Atcham Borough Council, supported by all seven district councils in Durham and most of those in North Yorkshire.

The Shropshire authority, which is also facing abolition under the national proposals, says it will be seeking a High Court injunction within days to halt the Government's consultation on the re-organisation while it seeks a full judicial review into the legality of the process later this year.

In March, Ruth Kelly, Secretary of State for Communities and Local Government, launched a fast-track consultation process in 13 shire counties, including County Durham, North Yorkshire and Northumberland, to end the two-tier system by which council functions are divided between district and county councils.

Supporters say the move, the biggest shake-up of local government in the region for 30 years, would save millions of pounds, reduce confusion and avoid duplication and waste.

But opponents say it would take decision-making away from the people and potentially cost thousands of town hall jobs.

A spokeswoman for the Department for Communities and Local Government said last night: "We cannot comment at the moment because we would not want to pre-empt the legal process, but we will respond in due course."

Robin Hooper, chief executive of Shrewsbury and Atcham Council, said: "The Government has failed to comply with Parliamentary procedure.

"The Secretary of State is trying to rely on a Bill before Parliament to justify action which would be a major constitutional change without Parliamentary approval.

"We have had polls in Shropshire and the people have categorically said they do not want this change. No reasonable secretary of state could reach this conclusion."

However, Mark Lloyd, chief executive of Durham County Council, which supports plans for a countywide unitary authority, said Shrewsbury's legal case was weak and mainly related to concerns specific to Shropshire.

He said: "In our case, both the county council and the Durham districts made applications to Government to move from an outdated model of two-tier local government to unitary local government.

"The county council's application was judged strong enough by Government for further consultation and sets out a bold new vision that would significantly benefit local people.

"In this light, I hope for the sake of the county's residents and businesses that the Shropshire situation has no bearing on an overdue and important possible change to local government in County Durham."

County Durham and North Yorkshire are widely regarded as among the most likely counties where the overhaul will be implemented, because they are two of three bids from across the country to meet all five of the Government's criteria for change.

But the proposed timetable for change, which would see a final decision made in July after a three-month consultation, has been criticised by opponents, as has the decision to consult "stakeholders" rather than the public. On Friday, Councillor Carol Woods, a member of the ruling Liberal Democrat cabinet on Durham City Council, hinted that the districts in Durham might organise a referendum on the issue.

She said: "I do think that we might gear up for a campaign to have a referendum of the people in Durham on whether they want a unitary authority or not.

"We want to make sure that people have enough information to make a decision. We will work with the Labour districts to call for a referendum.

"It is not necessary to do a whole structural reorganisation to get people to work together. "We think the best option is to retain the status quo."