Plans to build a £56m "science park" on the outskirts of Swindon have been turned down by planners.
Wasdell Group had threatened to leave the town if the scheme - which it said would create hundreds of news jobs - did not get the green light.
But the development on protected land attracted hundreds of letters of opposition from residents and planners recommended rejecting the scheme.
Swindon Borough Council voted to refuse the development on Tuesday night.
The company, which designs and produces specialist packaging and is based in the town, had applied to develop a 100-acre site between the A419 and Wanborough,
It said it would create 800 new jobs over the next two years, according to the Local Democracy Reporting Service.
Last week, the firm wrote to every Swindon councillor saying it would leave the town in 2021 and move its operations to Hampshire if it did not receive permission for the science park.
Planning committee chair, councillor Tim Swinyard, said the reasons for refusing the development had been "significant".
"This was actually putting it in a protected area, right by an area of natural beauty," he said.
"This would have changed the entire character, seriously damaging the local landscape."
Basingstoke move suggested
John Warr, from South Swindon Protection Group, said it was one of the "most highly protected areas" in Swindon.
"If you allow development on this land, than there is not a single piece of green land anywhere in the Swindon area, that would be protected," he said.
Martin Tedham, from the Wasdell Group, said the company has been "looking at facilities in Basingstoke".
"They can give us the land in Basingstoke where we can start building," he said.
"But we couldn't move a business like Wasdell in a year, it will be a few years before it could move."