Figures from the 2011 Grocery Retail Structure, released this week by IGD and William Reed Business Media, show that there were 2,589 Premier stores in April (when the survey was completed), putting Premier ahead of Spar for the first time.
Wholesaler Booker has been particularly effective in recruiting retailers to its Premier Express format for small stores, with numbers more than doubling from 165 to 463.
Since Premier was relaunched by Booker two years ago, the wholesaler has had the stated aim of making it the "biggest and best" symbol group.
Spar's store count was down 1% year on year to 2,576 (including Eurospar). with member recruitment and new store development not able to offset the loss of stores through acquisitions by other groups, notably the sale of the Botterills chain to Scotmid Co-op.
Overall, the total number of stores in membership of one of the UK's main symbol groups grew 2.9% to 16,288.