Walmart has confirmed Andy Clarke will step down from his post as chief executive and president of Asda in July.

Walmart China boss Sean Clarke will be taking over the role from 11 July. Andy Clarke will remain with Asda until the end of June – he will then serve as an advisor to the business until the end of 2016.

He will also continue to represent Asda as president of the IGD, a research and training charity that helps the food and grocery industry deliver the needs of the public.

Roger Burnley, previously thought a possible successor to Andy Clarke, will become deputy chief executive and chief operating officer when he joins Asda in October of this year.

Walmart said Andy Clarke had “decided the timing is right to step aside from his role with the company”.

David Cheesewright, president and chief executive of Walmart International, added: “We must have the right talent in place to lead our business through times of change.”

Last month the big four supermarkets all suffered a drop in sales for the 12 weeks to 24 April, with Asda faring the worst, according to Kantar Worldpanel.