He said a priority for the group would be increasing market share and denied that competition from other new entrants, such as Sainsbury and Tesco, threatened to saturate the market.
Marwood said: "There are loads of potential sites, and potential members. When we do get round to putting down markers in terms of absolute targets I think they'll be big ones."
He suggested London represented a big opportunity for Spar because there was a far lower density of stores in the capital than in the rest of the UK. Forecourts could also present a rich recruiting ground, he said, because oil companies had realised consumers were not happy buying food from petrol brands.