The challenge will focus on the legality of proposals drawn up by county councils to cut the numbers of libraries in their areas, says legal firm Public Interest Lawyers (PIL).
The application for judicial review is expected to be the first of its kind and questions the ability of David Cameron’s Big Society, with its “vague notions”, to deliver statutory services to the public.
PIL, acting on behalf of local library users, has sent a letter before action challenging the reliance of the two shires “on Big Society community-transfer initiatives” which conflicts with their “clear statutory obligation to provide a comprehensive and efficient library service for everyone wanting to use it”.
The firm’s lawyers also argue that the councils did not consult properly with local people prior to making the decision to cut, or pay proper attention to the needs of vulnerable groups.
PIL said in a statement: “Gloucestershire County Council proposes to reduce the number of libraries with full opening hours from 38 to nine, and to cut the mobile library service for persons in rural areas entirely.
“Somerset County Council initially proposed to cut 20 of 34 libraries and to reduce mobile libraries from six services to two.
“They have since announced that the cuts will be reduced to one third of libraries, but without showing how this would be financed.”
PIL solicitor Phil Shiner said: “Councils cannot pin their hopes on vague notions of the Big Society when they are required by Parliament to maintain a comprehensive and efficient library service for everyone in the county.”
The application for judicial review is expected to be launched at the High Court in London within a few weeks.