Coors Brewing, the British arm of the American brewer Adolph Coors, is to close the former Mitchells & Butlers brewery in Cape Hill, Smethwick by the end of the year.

The plant, which employs 320 people in brewing, canning and bottling, is one of four British breweries Coors acquired for £1.2bn this year when it bought the parts of the old Bass brewing empire that Interbrew was forced to sell to satisfy competition concerns.

Coors said 70% of production at Cape Hill was Bass pale ale for export, a brand that Interbrew kept when it sold Carling, Worthington and other beers to the Americans. Interbrew is transferring 1m barrels of production from Cape Hill to its own British breweries later this year, which Coors said made Cape Hill unviable.

The three other Coors-owned breweries, at Tadcaster, Burton upon Trent and Alton in Hampshire will remain open, Coors said, and up to 100 jobs will be created at Burton as Cape Hill is wound down.

Coors said the cost of the closure would be between $21m and $28m, but it expects savings of between $16m and $21m starting in the second quarter of 2003. It is offering the breweries employees help in finding jobs inside and outside the company.

It insisted its action in closing just one brewery was relatively benign, saying: "If venture capitalists had gotten their hands on the breweries they would have been far, far more vicious."