Whole Foods: Are two heads better than one in business?

Most big companies have a boss at the top, who controls everything down to the bottom.

But is that really the best way of leading global enterprises? One company that takes a different approach is the giant US food retailer Whole Foods Market.

Instead of having one chief executive, or CEO, they have two. Leadership expert Steve Tappin asks whether this approach can work over the long term and should other businesses take note?