Christchurch BC has launched a legal challenge to plans for a reorganisation of local government in Dorset.
In February, local government minister Sajid Javid confirmed he would go ahead with proposals to replace nine councils in the county with two new unitary authorities.
The new councils are due to start work next April, one covering Bournemouth, Christchurch and Poole and the other serving the rest of Dorset.
But following Mr Javid's refusal to withdraw the plans, Christchurch has now issued proceedings in the High Court for a Judicial Review of the decision.
Council leader David Flagg said: 'Christchurch Borough Council and the majority of our residents remain opposed to local government reorganisation in Dorset and we firmly believe that the regulations drafted by the Secretary of State are beyond his powers.'