An insurance company has been given permission to build nearly 200 homes on land which used to form part of the Cheshire green belt.
Royal London wants to develop land adjoining its headquarters in Wilmslow.
The proposals are part of the company's wider plans that will see it transfer all 1,200 staff from the site to nearby Alderley Park.
Campaign group Residents of Wilmslow said it was preparing to take legal action against the plans.
Spokesman Manuel Golding said people living nearby were "more than annoyed, to the point they are now instructing counsel" to apply for injunctions against the proposals.
Cheshire East councillors considered plans for two separate parcels of land on Alderley Road, both of which lost their green belt status last year under a Cheshire East Council strategy to meet house-building targets.
Wilmslow councillor Toni Fox said Royal London had put "a certain amount of pressure on the council".
"They were going to leave the site and move out of the borough," she told a planning meeting.
Gary Halman, representing Royal London, told the meeting the land was "removed from the green belt by Cheshire East Council to specifically help deliver local housing needs".
A report prepared by council officers said the plans for up to 195 homes were "environmentally, socially and economically sustainable and accord with the development plan and the framework".