Tesco is set to steal Metro's crown as the world's third largest food retailer.

Planet Retail's Top 30 Grocery Retailers 2006 report predicts Tesco's global market share will grow from 1.5% to 2% in the next five years as it continues to expand its

international operations.

Metro's market share is expected to rise from 1.5% to 1.7% by 2012, dropping it to fourth place on the chart. Metro is currently just ahead of fourth-placed Tesco because the value of its retail sales are higher.

"Tesco continues to defy the competition," said Planet Retail analyst Natalie Berg. "Its rising presence is being felt across Europe and Asia, with entry into the US later this year."

Wal-Mart and Carrefour are in first and second place, respectively, with market shares of 6.3% and 2% - they are expected to rise to 6.6% and 2.2% by 2012.