Hampshire County Council is challenging the government’s local government reorganisation plans in court, arguing ministers have failed to provide evidence to support their decision.

The move marks a major escalation in the row over local government reorganisation (LGR), which will replace the current two-tier system of county and district councils with a smaller number of unitary authorities.

Under proposals, existing councils would be abolished and replaced by new authorities responsible for delivering all local government services.

The reorganisation will affect more than two million residents and determine how services such as social care, education, highways, waste collection and planning are delivered and funded for decades to come.

However, the county council leader, Cllr Nick Adams-King, has consistently argued that the government has not provided sufficient evidence to justify its preferred model and have raised concerns about the long-term financial sustainability of the proposed arrangements.

Cllr Adams-King said: “We have repeatedly asked Government to disclose the financial evidence behind the Secretary of State’s decision. That information has not been provided.

“The government responses to date have raised more questions than they have answered. Judicial review is now the only mechanism available to obtain that evidence, test the decision-making process and establish whether the decision was lawful.

“This is not about preserving the existing system, nor about returning to Hampshire County Council’s preferred plan. It is about ensuring the councils which succeed us are financially sustainable and capable of protecting the services upon which residents rely.

“The chosen model removes valuable communities, development opportunities and business rate income from Mid Hampshire while leaving it with a more rural geography, an older population and higher service delivery costs.

“We recognise the cost of legal action, but getting reorganisation wrong could cost Hampshire taxpayers tens, if not hundreds, of millions of pounds over the next decade.

“Residents deserve a lawful, transparent and evidence-based decision. Judicial review is now the only way to secure those answers.”

The decision has received support from Reform UK. Its leader Cllr George Madgwick acknowledged concerns about the cost of court proceedings but argued that the financial consequences of an unsuccessful reorganisation could be far greater.

He said: “We know people will ask about the cost, and it’s a fair question, but the cost of getting this wrong could be far higher.

“If government pushes through with its decision, local people could end up paying the price through higher bills and less money for everyday services like road repairs, school transport and social care for vulnerable children and adults, reaching into tens of millions of pounds.

“That’s why we believe government must properly justify the Secretary of State’s decision.

“Reform UK is entirely against LGR implementation in its current form and will do what we can locally to fight it, without recklessly spending money where there is no chance of success. We will review our position constantly based on legal advice as it becomes evident.”