Legal proceedings could be brought against the government after there was fury at the latest development in Bucks’ journey towards becoming a unitary authority.

It was revealed that the leader of the county council, Martin Tett, will take the helm of a new “shadow” authority set up to steer the transformation.

In a letter to all five councils sent on January 7, secretary of state for housing James Brokenshire confirmed a temporary ‘shadow’ authority will be formed, with all 202 current county and district councillors having a seat on the body and Mr Tett leading the 17-seat shadow executive.

It sparked fury among district councillors, who branded the decision “deeply disturbing”.

Now, Wycombe and Chiltern district councils have written to Mr Brokenshire as a preliminary step to legal proceedings.

In a statement, the two councils said: “The district councils were very disappointed with the recent decision of the secretary of state regarding the way in which the new unitary council will be set up.

“All four district councils decided at recent meetings of their cabinet not to consent to the regulations which were laid before Parliament on Monday.”

The letter raises specific concerns about the “lack of local consent”, the recent changes to what was proposed and the “lack of reasons” given for making them, and a “failure” to ensure appropriate checks and balances.

Last November, Mr Brokenshire announced a single unitary council for the county, which will replace the current county council and four district councils, and be named The Buckinghamshire Council.

In a joint statement, Cllr Isobel Darby, leader of Chiltern District Council and Cllr Katrina Wood, leader of Wycombe District Council, said: “We are doing this with great reluctance but feel that the MHCLG [ministry of housing, communities and local government] has left us with no alternative.

“We have obviously thought long and hard about whether to take this step. But in this case we believe that it is in the best interests of our communities in Buckinghamshire to challenge the process being used.

“Our aim is not to hinder the creation of the new council but to ensure we get an excellent, new council, giving us the opportunity to start afresh and form a council that serves our residents and businesses well, and one we can be proud of.”