David Wild has left Wal-Mart to take the top job at UK firm Halfords.

The news could be a significant blow to the US retailer as Wild, a former Tesco executive, headed-up Wal-Mart's new Marketside stores format in California.

Wal-Mart had positioned the smaller-scale Marketside stores to compete with Tesco's Fresh & Easy in the hopes of halting Tesco's US advance. Marketside outlets were preparing to debut in Phoenix later this year, where they would go head-to-head with Tesco.

Fresh & Easy operates stores across California, Nevada and Arizona. Tesco has indicated that it plans to have opened 200 outlets by the end of the year.

Wild will become CEO of Halfords in August. He is the successor to Ian McLeod, who left Halford's to run Australia's number two grocer Coles in February. 

"Mr Wild brings over 20 years' retailing experience, gained at two world-leading businesses and clearly has the skills and ability to move the company forward," Richard Pym, Halford's chairman, said.

Wal-Mart was unavailable for comment as just-food went to press.