A council opposed to plans to merge it into a unitary authority has launched its application for a judicial review.
Shrewsbury and Atcham Council said the official papers have been sent to the High Court and the formal papers could be served on Monday.
The government recently unveiled a shortlist of councils applying for unitary status, which included Shropshire.
If approved, the county's five district or borough councils would disappear.
The council says it is challenging the process on the grounds that the government does not have the power to undertake the review and that the review has been unfair and unbalanced.
In previous local consultations Shropshire County Council, Oswestry Borough Council and South Shropshire District Council supported the move to have one council.
Shrewsbury and Atcham Borough Council, North Shropshire District Council and Bridgnorth District Council opposed it.