LONDON — The British Broadcasting Corp. announced yesterday it will cut 1,800 jobs, broadcast fewer programs, and require staff to create content for television, radio, and the Internet, creating a showdown with journalists and other employees.

Union leaders vowed to strike if the BBC went forward with the radical overhaul, which includes major cutbacks to news and documentary divisions. BBC journalists say the cuts threaten the quality of the broadcast, and the union said a strike vote could begin Friday at noon.

The BBC’s director-general, Mark Thompson, told staff that 2,500 jobs will be cut over the next six years, but that 700 new jobs will likely be created.

The job cuts represent about 8% of the corporation’s 23,000 positions. Up to 490 jobs will be cut in the BBC news operations; 725 jobs will be cut in the factual programming division, which produces documentaries and other nonfiction programs; and up to 975 across regional outlets, according to the plan.

The BBC will cut the number of programs it commissions by 10%, which will save about $203 million annually, according to the plan.

“Media is transforming. Audiences are transforming. It would be easy to say that the sheer pace of this revolution is too fast for the BBC,” Mr. Thompson said.

“I believe we will look back at today in a few years time as the moment when the BBC did make some difficult choices,” he said.