Simon King, the chief operating officer at Asda, has left the grocer after less than six months in the role, in a move that has sent shockwaves through the sector.
The former Tesco executive only joined the Walmart-owned grocer in January but left the Leeds-based supermarket this morning. Asda confirmed Mr King's departure but declined to provide reasons.
At Asda, Mr King's responsibilities included retail, supply chain, including distribution, and customer service.
Before Asda, he was the chief executive of the supermarket operator Panda Retail, a subsidiary of the Saudi Arabia-based Savola Group.
The next move for Mr King is unclear. He had previously been chief executive of Tesco's Kipa chain in Turkey until 2009.