Walkouts will start in Los Angeles, Chicago, and Seattle, after union said it was making little progress with chain’s owners over pay and conditions

Workers at Starbucks stores in three cities plan to go on strike Friday after a union representing more than 11,000 baristas in the US said it was making little progress with the giant coffee chain’s owners over pay and conditions.

The walkouts will start in Los Angeles, Chicago, and Seattle, with strike action set to spread each day and, subject to a deal, reach hundreds of stores by Christmas Eve.