The retailer is currently piloting eight Simply Food stores on BP forecourts and reports suggest that if the roll-out goes ahead, the number of stores could total more than 500 within a few years.
However, M&S refused to confirm the plans, adding that it was “considering its options”.
The reports follow yesterday’s acquisition of 28 stores from food retailer Iceland for £38m.
The deal is set to be completed in March and the stores, which all average 5,000 sq ft, will be refitted between June and August.
M&S said that the stores would help its to expand its Simply Food format.
M&S already operates 143 Simply Food stores in the UK, Republic of Ireland and the Channel Islands, including 40 franchise stores in railway stations, petrol forecourts, airports and motorway service stations.
Meanwhile, Iceland yesterday reported a 16.1% increase in underlying sales and a 10.8% increase in total sales for December.