Cumbria County Council has voted against proceeding with plans to build an underground nuclear waste dump.
Council leaders rejected a move to the next stage of studying a possible suitable site by seven votes to three.
There were huge cheers from environmental campaigners outside the council chamber in Carlisle when the decision was announced.
More than 32,000 people had signed a petition against the £12bn underground storage facility.
Greenpeace energy campaigner Leila Deen said: "This decision represents yet another major blow for the Government's attempts to force the construction of costly nuclear power plants.
"Even the Prime Minister admits we need a plan to store waste before we can build a single new plant.
"This decision shows that dumping waste in uncertain geology near one of the country's most pristine national parks is not a solution.
"Ministers must now reconsider their nuclear ambitions and turn their attention instead to clean, sustainable and renewable energy."
Earlier, Copeland borough council voted six to one in favour of moving to the next stage in the search for a site to bury radioactive waste.
But the Cumbria County Council vote overrides any decisions taken by borough authorities in the area.
If the site had been given the go ahead it would have been the first of its kind in the UK. Currently most nuclear waste is stored at Sellafield in Cumbria.
Cumbria Council leader Eddie Martin said: "Cumbria has a unique and world-renowned landscape which needs to be cherished and protected.
"While Sellafield and the Lake District have co-existed side by side successfully for decades, we fear that if the area becomes known in the national conscience as the place where nuclear waste is stored underground, the Lake District's reputation may not be so resilient."
Deputy Leader Stewart Young added: "The case for investment in Sellafield is now more pressing than ever.
"We had always raised concerns over the lack of any plan B from Government and the fact that West Cumbria was the only area to express an interest in the process left the Government with few options if we decided not to proceed.
"It is now time for the Government to secure the long-term future of the nuclear industry and put in place robust storage arrangements at Sellafield while it decides how to continue the search for a repository elsewhere in the UK."
Energy Minister Ed Davey said the Government will continue to work with communities to find a waste site.
"There is support out there some communitites realise there's a huge economic benefit for their area.
"We already store a huge amount of waste from the last six decades. We store it safely, but we wanted a long-term storage process and we're going to work with other communities to do just that."
As councillors were meeting, protesters gathered to make their views heard.
Cumbria resident Miles Fielding told Sky News: "There are already problems in the continent where there are nuclear dumps with leakage and known cancers occurring in the villages where the dumps are, so it's just not worth playing with."
Also outside the meeting were people staging a demonstration in favour of the plans because of the jobs a new site would create.
Garry Graham, deputy general secretary of Prospect, which represents 12,000 nuclear workers, said: "A decision not to proceed to the next stage of feasibility studies will take us straight back to the drawing board.
"The alternative to building a repository is not no radioactive waste, just continued surface storage. Therefore, the assessment of the scientific case for a geological disposal facility needs to weighed against the pros and cons of the alternatives.
"The next stage consists of experts conducting desk-based geological studies, compiling a waste inventory and discussions over the social and economic implications.
"It is still a long way from a green light for any excavation or exploratory groundwork.
"Not only does the vote have vast implications for the economic wealth of West Cumbria, which relies so heavily on the nuclear industry for jobs and growth, it potentially casts a shadow over any nuclear renaissance in the UK."