Legal charity the Public Law Project is supporting a judicial review challenging Cumbria County Council's decision to require day care services that it funds, including charities, to introduce means-tested charges.
The project says the decision breaches the Compact - the agreement between government and the voluntary and community sector - because there wasn't adequate consultation.
The case, brought by an Age Concern South Lakeland service user, could set a precedent if the judge takes into account the alleged Compact breach and rules against the council, legal experts have said.
"We will be trying to get the judge to consider the Compact quite specifically," said Louise Whitfield, project solicitor at the PLP.
The case for enforcing the Compact rests on a public law principle of whether charities and voluntary bodies have a 'legitimate expectation' that councils should abide by the agreement.
Jess Crocker, local Compact advocacy officer at the Compact Advocacy Programme, said the case was an exciting one for the sector.
"If the Compact is mentioned as part of the legal proceedings, that could be very significant," she said. "It is really important that the legal position becomes clear and councils understand they cannot breach the Compact."
Richard Corden, interim chief executive at the Commission for the Compact, said the legal status of the Compact should be addressed. "When it comes to legal remedies, we are in a grey area - this is one thing that I think needs clarifying urgently," he told delegates at the Association of Charity Officers' annual conference last week.
The case comes as the Office of the Compact Commissioner, which promotes and reviews the policy and operation of the Compact, seeks a new chair and chief executive. Former chair John Stoker resigned last week for personal reasons (Third Sector Online, 7 September), three months after the departure of the commission's first chief executive, Angela Sibson (Third Sector, 18 June).