Fisher will retain his spirits and tobacco buying responsibilities, expanding his role from April 8. Steve Wallace will continue to buy all beer, lager and cider, but will now report to Fisher, who joined the retailer in 2004.
Mark Williamson, BWS head of buying, said: "Giles's new role will ensure that we continue seeking out high quality, local and unusual lines, across both beers and spirits. We will stay dedicated to understanding what our customers want and offering good value for money as well as market -leading quality."
The move follows Justin Howard-Sneyd MW's promotion to wine buying manager last year.