Starbucks said the new rules would make its green aprons stand out and create a sense of familiarity for customers as it tries to establish a warmer, more welcoming feeling in its stores.

Hundreds of Starbucks baristas are walking out across the country after the coffee chain enforced a new dress code policy this week.

The company promised to provide staff with two free black T-shirts, which the union is claiming many employees have not yet received.