A High Court ruling has forced Lincolnshire County Council to rethink its decision to turn 30 libraries into community-run hubs.
Lincoln carer Simon Draper had challenged the authority's decision to change the libraries service in a bid to save £1.7m.
However, at the High Court this morning, Mr Justice Collins ruled the council needed to reconsider its decision after hearing legal arguments in a two-day hearing earlier this month.
The court set aside the original decision meaning that proposed changes to services will need to be reviewed by the council's executive after an additional period of consultation.
Campaigners argued in court that a proposal from Greenwich Leisure Limited to run all of Lincolnshire's libraries while still saving money was ignored and that the council's plan would restrict vulnerable group's access to libraries.
Following the ruling, Mr Draper said: "I'm overwhelmed and ecstatic.
"After the first day of the hearing we were really worried that it was not going our way then we heard council's barrister say their piece on day two and we were a bit more optimistic.
"We have the result we wanted."
Court number one at the Royal Courts of Justice was packed as the judge announced his decision and campaigners thanked him as he left court.
Mr Draper - who cares full time for his disabled wife and is a regular user of Lincoln Central Library - argued the changes would leave thousands of Lincolnshire residents more than half-an-hour away from their nearest library and would cost hundreds of jobs.
However, the council said it had to make savings and had attacked Mr Draper's challenge as "misconceived".
The judge said: "The overwhelming objection to the decision does not in itself mean that it is unlawful.
"The decision to make the £2 million cuts was a political one which was not and cannot be challenged in the courts."
Upholding Mr Draper's challenge, however, he identified "shortcomings" in the public consultation process - despite all the council's efforts to make it legally bullet-proof.
A critical aspect of the proposals was already set in stone by the time residents were asked for their views and, although Greenwich Leisure's proposals were only at a formative stage, the council was obliged to fairly consider them.
The judge concluded: "The decision must be quashed. The council must, I fear, reconsider.
"It may be that the most sensible way ahead is to obtain the necessary further details from Greenwich Leisure and perhaps consult further for a shorter period on whether any overall alternative proposal is forthcoming.
"That is a matter for the council"
Richard Wills, Executive Director at LCC, said: "We are, of course, disappointed with the decision.
"We believe that our proposals would have increased library provision in the county, while also making substantial savings, meaning taxpayers would be getting a much better deal.
"The judge agreed there was a need to make savings, that our proposals would meet our statutory duties and that we'd carefully considered the impact on all residents.
"However, his decision means we will now need to undertake further consultation and re-examine the proposal from Greenwich Leisure Ltd.
"Ironically, although we must consider that proposal as a community offer to take over the council's services under the Localism Act, it could lead to the library service being put out to procurement and outsourced to a commercial organisation.
"We will now address the points raised by the judge and remain open-minded.
"However, we need to take time to consider the best way forward, and will announce our next steps in the near future.
"In the meantime, we'll continue to keep in close contact with the communities wanting to become involved in running library services.
"What this judgment doesn't change is the need for us to find further yearly savings of £90m by 2018."
The judicial review has so far cost the council an estimated £60,000 to £65,000.
For more on the proposed changes to library services, visit www.lincolnshire.gov.uk/librariesconsultation
